Indonesians are voting in the country's second direct presidential election since the overthrow of the Suharto regime in 1998.
Voting has been taking place in Indonesia's second direct presidential election since the overthrow of the Suharto regime in 1998.
Opinion polls have given incumbent President Susilo Bambang Yudhoyono a comfortable lead over his rivals.
Initial exit polls give incumbent President Susilo Bambang Yudhoyono a comfortable lead over his rivals.
He faces challenges from former president Megawati Sukarnoputri and outgoing Vice-President Jusuf Kalla.
Former President Megawati Sukarnoputri and outgoing Vice-President Jusuf Kalla are also contesting the poll.
More than 250,000 police and 20,000 soldiers have mobilised across the Indonesian archipelago.
More than 250,000 police and 20,000 soldiers were mobilised across the archipelago ahead of the vote.
Security is reported to be especially tight in the provinces of Aceh, in the far west, and Papua, in the far east, both of which have experienced unrest in recent years.
Security was reported to be especially tight in the provinces of Aceh, in the far west, and Papua, in the far east, both of which have experienced unrest in recent years.
About 176 million people have registered to vote at more than 500,000 polling stations. The first polling stations opened in Indonesia's easternmost region, Papua, on Wednesday morning.
About 176 million people had registered to vote at more than 500,000 polling stations. The first polling stations opened in Indonesia's easternmost region, Papua, on Wednesday morning.
'Better future'
Corruption-free?
Unregistered voters will also be able to use their identity cards to cast a ballot, after the Constitutional Court relaxed rules on voter registry on Monday.
Soon after voting ended, initial exit polls gave Mr Yudhoyono a clear lead, with more than 50% of the vote.
If these preliminary indications are right, he will avoid a second round run-off in September.
The decision followed a complaint by Mr Kalla and Mrs Megawati, who said millions of people had been left off voter lists.
Support for his Democratic Party surged to more than 20% at parliamentary elections in April.
In a reaction to the ruling, Mr Yudhoyono called on voters to make the election a success.
"Tomorrow is your day... You who have the right and opportunity to vote freely without intimidation and pressure from anyone," he said on Tuesday.
Ms Megawati appealed to Indonesians to vote with a "clear and honest mind."
"We are convinced that we can create a better future," she was quoted as saying by AFP news agency.
Mr Yudhoyono, a 59-year-old former general, was elected in Indonesia's first direct election in 2004, defeating then-President Megawati.
Mr Yudhoyono, a 59-year-old former general, was elected in Indonesia's first direct election in 2004, defeating then-President Megawati.
He has been boosted by the success of the economy and a corruption-free image, correspondents say.
He has been boosted by the success of the economy and a corruption-free image, correspondents say.
Some opinion polls have suggested that he could surpass the 50% of votes needed to avoid a second round run-off in September.
Support for his Democratic Party surged to more than 20% at parliamentary elections in April.
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