Ukraine has been gripped by months of mass protests, finally forcing President Viktor Yanukovych out of power last week - after several days full of drama and changes at breakneck speed.
After months of mass unrest in Ukraine, culminating in deadly violence and the removal of the elected president, Viktor Yanukovych, we look at some of the key players emerging.
The unrest was triggered by Mr Yanukovych's last-minute rejection of a landmark deal with the EU in favour of stronger ties with Russia in November 2013.
Oleksandr Turchynov, acting president
The demonstrations have united pro-EU and ultra-nationalist leaders, but have also brought to prominence groups of activists at the main protest camp in Kiev - the Maidan.
Propelled to the top by the collapse of the Yanukovych administration, the new parliamentary speaker and acting president is considered the right-hand man of Yulia Tymoshenko, who was Mr Yanukovych's arch-rival at the 2010 presidential election.
Here we profile both some of the key opposition leaders and Maidan activists.
An important figure in the 2004 Orange Revolution, the 49-year-old briefly served as head of the domestic security agency, the SBU, then as a deputy prime minister.
Vitali Klitschko
While he may enjoy street cred with some protesters - he was injured in the face by shrapnel during the violence in Kiev this winter - he appears to lack charisma and is not ultimately seen as a presidential candidate.
The former world heavyweight boxing champion has until recently been arguably the most prominent figurehead of the protest on the Maidan (Independence Square).
Yulia Tymoshenko, former prime minister
Mr Klitschko heads the Ukrainian Democratic Alliance for Reforms (Udar), whose acronym means "Punch". The pro-EU party came third in the 2012 parliamentary elections. It campaigns against what it perceives to be rampant government corruption.
Freed from prison after the fall of Mr Yanukovych, the 53-year-old former prime minister has ruled out returning to office as prime minister.
Mr Klitschko, 42, has rejected the role of deputy prime minister offered by Mr Yanukovych, calling it a "poisoned" gesture aimed at splitting the opposition.
With her Fatherland party the second-largest party in the current parliament, she is seen as a strong contender at the next presidential election.
He has been a vocal Yanukovych critic, accusing him of nepotism and deliberately sabotaging the country's EU ties.
However, the former star of the Orange Revolution was defeated in 2010 in a vote considered free and fair by outside observers. As a former figure in the gas industry establishment, she is regarded with suspicion by some sections of the movement which brought down Viktor Yanukovych.
"The system today is built to service the clan, the family, and not society as a whole," Mr Klitschko said in a recent interview.
Health problems may also dog any hopes she has of becoming president.
Mr Klitschko, nicknamed Dr Ironfist, holds a PhD in sports science and plans to run in the 2015 presidential elections.
Arsen Avakov, acting interior minister
However, his popularity has recently waned, with some Maidan activists criticising him for being indecisive and ready to strike deals with the authorities.
Another member of Tymoshenko's Fatherland party, the 50-year-old former businessman said his primary task as minister was to restore order in the country.
Oleh Tyahnybok
He is expected to focus on an inquiry into the mass shooting of demonstrators in Kiev on 18-20 February.
The leader of the far-right Svoboda party (meaning Freedom), Oleh Tyahnybok, regularly appears alongside Mr Klitschko as one of the key protest participants.
The ethnic Armenian is an active Facebook user and has been posting Russian-language updates on the hunt for Mr Yanukovych and other investigations even before official sources are told.
His movement was a shock success in the last parliamentary election. It won 37 out of 450 parliamentary seats to become Ukraine's fourth-largest party.
Oleh Makhnitskyy, acting chief prosecutor
Previously known as the "Social-National Party", Svoboda promotes itself as a fervent defender of traditional Ukrainian culture and language against foreign influence - and is seen by some as a fascist organisation.
The 43-year-old member of the far-right Svoboda party was little known on the national political scene before his appointment by parliament.
Mr Tyahnybok, who insists that Svoboda is neither xenophobic nor anti-Semitic, was expelled from parliament in 2004 for proclaiming that a "Muscovite-Jewish mafia" controlled the country.
A lawyer from Lviv, he worked as an investigator with a local prosecutor's office in the late 1990s before moving into politics.
On 1 January 2014, thousands of Svoboda supporters caused controversy when they held a torch-lit procession in Kiev to mark the birthday of a World War Two-era partisan leader.
Viktor Yanukovych, ousted president
Some analysts believe the party's participation in the protests contributes to Ukraine's political divide, as their base of support is mainly in the country's west, while voters in the east and south view them as extremists.
Reduced to a fugitive by the success of the opposition movement in Kiev, the 63-year-old is said to have fled the capital for Crimea, a stronghold of his ethnic Russian supporters.
Fatherland
He insists he remains the "legitimately elected president" and is the victim of "banditry and a coup d'etat".
Ukraine's largest party after the disintegration of Mr Yanukovych's Party of Regions is led by former Prime Minister Yulia Tymoshenko, an arch-rival of Mr Yanukovych.
After a humiliating defeat during the Orange Revolution, he came back in 2010 with a strong electoral mandate.
A heroine of the 2004 Orange Revolution, she was sentenced to seven years in prison in 2011 for abuse of power. Her supporters say this was simply Mr Yanukovych taking out his most prominent opponent.
However, it is difficult to see how he could return to power now, after alienating former supporters through his weak economic policy and antagonising opponents with his orientation towards Russia.
She was finally freed last week.
Vitali Klitschko, candidate
The EU had demanded that Tymoshenko - who suffers ill health - be allowed to leave the country for treatment, and made this a pre-condition for signing its proposed trade deal with Ukraine.
Aged 42, the former boxer is the first figure from the anti-Yanukovych movement to declare his hand in the next presidential election.
Tymoshenko remained politically active in jail, releasing several fiery statements rejecting any compromises with the Yanukovych authorities.
One of the most recognisable faces of the winter protests, the anti-corruption campaigner leads the third-biggest party in parliament, Udar.
But imprisonment has stifled her voice, and there was no triumphant return when she finally appeared and spoke in front of the crowds on the Maidan last week.
But on the streets, he was accused of indecisiveness and being too ready to strike deals with the authorities.
Many analysts still see her as the most likely presidential challenger in snap elections on 25 May - but critics say she is no solution to Ukraine's problems, and that her own hands are dirty.
Mykhaylo Dobkin, candidate
A close ally of Tymoshenko, Arseniy Yatsenyuk is the parliamentary leader of the Fatherland party, and has been its main negotiator during the protests.
Few outside Ukraine may have heard of the governor of the Kharkiv region but if there is a pro-Russian mantle to inherit, the 44-year-old may be in contention.
The 39-year-old said there had been "no deal" on the table despite being offered the post of prime minister by Mr Yanukovych before he was ousted.
Declaring that he would stand in the next election, he said the rights of the country's Russian-speaking population were under "total attack".
Instead, Mr Yatsenyuk vowed to press on with the protests until all demands had been met.
"Laws are being adopted that threaten all those who do not accept fascism and Nazism," he said, as the new authorities moved to remove the special status of the Russian language.
"We're finishing what we started," he said in a tweet.
As a leading member of the Party of the Regions, the ruling party under Mr Yanukovych, he would have a strong power base in eastern Ukraine but he will be tarnished in the eyes of many by his close relations with the deposed leader.
Like Mr Klitschko, Mr Yatsenyuk campaigns for EU integration and to rid Ukraine of corruption.
Arseniy Yatsenyuk, Tymoshenko ally
The former lawyer has held top posts in previous governments, including foreign minister and governor of the central bank.
As parliamentary leader of Ms Tymoshenko's Fatherland party, the 39-year-old was its most prominent figure during the protests.
Mr Yatsenyuk unsuccessfully ran for president in 2010.
A former lawyer, he has held top posts in previous governments, including foreign minister and governor of the central bank.
A close ally of both Tymoshenko and Mr Yatsenyuk, Oleksandr Turchynov has now been elected parliamentary speaker and given responsibilities of acting president.
In a famously intercepted phone call, US envoy Victoria Nuland described him as the "guy who's got the economic experience, the governing experience".
The 49-year-old held a number of key positions in the "Orange Revolution" government, including being in charge of the security services.
However, his future may not lie with the presidency. When he stood at the first round of the 2010 presidential election, he won less than 7% of the vote.
Mr Turchynov, who was injured in the face by shrapnel during clashes in Kiev, is expected to continue to play a prominent political role, but is not seen as a presidential contender.
Oleh Tyahnybok, far right leader
The 48-year-old successful businessman was a prominent figure during and after the Orange revolution, holding key government positions - including that Ukraine's foreign minister.
The leader of Svoboda regularly appeared alongside Mr Klitschko and Mr Yatsenyuk on the stage in Kiev's Independence Square, while party activists were prominent among the demonstrators.
Mr Poroshenko - nicknamed a "chocolate king" for his Roshen sweets - returned to parliament in 2012 as an independent.
The 45-year-old was expelled from parliament in 2004 for proclaiming that a "Muscovite-Jewish mafia" controlled the country and his party is seen by some as a fascist organisation.
During the latest unrest, his Channel 5 TV has played a key role in covering the most dramatic events.
At the parliamentary election in 2012, Svoboda won 37 out of 450 parliamentary seats to become Ukraine's fourth-largest party.
Mr Poroshenko is seen by many as a "dark horse", who may bring about a few surprises.
However, he himself had won just 1.4% of the vote when he stood for president in 2010.
Ukraine's ex-Interior Minister Yuriy Lutsenko made headlines in mid-January when he was badly hurt during clashes with riot police.
Dmytro Yarosh, radical organiser
Although the vocal opposition leader does not belong to any political party, he is closely affiliated with the Fatherland party.
The 42-year-old leads the paramilitary movement known as Right Sector, which was involved in violent clashes with the police in Kiev and considers Svoboda "too liberal".
The 49-year-old's rise to prominence began with the Socialist Party in the early 1990s. He later became one of the most recognisable figures involved in the Orange Revolution, and a prominent member of Tymoshenko's pro-Western government.
Advocating a "national revolution", he dismissed the Yanukovych administration as an "internal occupation regime".
Like Yulia Tymoshenko, he himself was jailed for abuse of office and embezzlement, but pardoned under EU pressure in April 2013.
He wants to ban both the former ruling party and its ally, the Communist Party.
After leaving jail, he set up a "civic movement" called the Third Ukrainian Republic, which analysts say could be a sign of growing political ambitions.
Petro Poroshenko
The Maidan overall commander have been in the midst of all the most dramatic events in Kiev: helping his self-defence fighters to repel police attacks, building up barricades and organising the logistics of the camp.
A successful businessman, the 48-year-old has held government posts under successive presidents.
The 43-year-old was wounded during the clashes, but stayed on with the activists.
Nicknamed the "Chocolate King" because of his confectionary business, he also controls a TV channel which played a key part in the protests, Channel 5.
He commands a huge respect among the protesters, but has so far not announced any plans to move into the new government structures.
He is seen by some as a "dark horse".
Right Sector
In the early days of the protests in Kiev, the most radical activists on Independence Square created the Right Sector movement, which has taken an active part in violent clashes with police.
Led by Dmytro Yarosh, the group consists mostly of young men with right-wing views. They come from different regions of Ukraine, and there are both Ukrainian- and Russian-speakers among them.
The members often wear masks, helmets and protection for their hands and feet, and carry sticks or iron bars in case of confrontation with riot police.
Unlike other protesters, most of the Right Sector activists do not support the idea of joining the EU, which they consider to be an "oppressor of European nations".
The organisation believes the current situation is an opportunity "to destroy the state skeleton" and start building a new state.
The Right Sector does not associate itself with the nationalist Svoboda, which it considers to be too liberal and conformist.
AutoMaidan
The group emerged soon after the unrest, with its driver-members helping ferrying food and medicine to the Maidan camp, and later also transporting the injured to hospitals.
Moving in motorcades, the AutoMaidan has provided an invaluable help with reconnaissance about police movements and has paid visits to the palatial residences of top Yanukovych figures - which proved to be highly embarrassing for the officials.
Dmytro Bulatov, one of the leaders of the group, was abducted and badly beaten by unknown assailants. He is currently being treated abroad.
Despite the removal of Mr Yanukovych, the AutoMaidan says it will stay "in opposition" to the new authorities, checking all their actions.
