Nato forces say they have killed 48 Taleban insurgents in renewed fighting in southern Afghanistan.
Scores of civilians have been killed during Nato operations against Taleban fighters in southern Afghanistan, local officials and civilians say.
A number of civilians are also reported to have died. Nato said there had been three separate clashes in the province of Kandahar.
The Afghan Defence Ministry has launched an investigation into the reported deaths in Kandahar province.
But senior Taleban commanders have told the BBC they believe they are winning the battle with British forces.
Nato said it had "credible reports" of civilian casualties but could not confirm reports of 50 dead civilians.
In a rare interview, one rebel leader said suicide attacks would increase, with up to six taking place at a time.
The alliance said 48 militants had been killed. In September it said it had routed the Taleban in the area.
The BBC's David Loyn met Taleban fighters in Helmand and reports that they had new vehicles and communications equipment.
Nato said there had been three separate clashes this week in Kandahar province.
Travelling with the Taleban Haji Mullah Wahidullah, a senior figure in the movement in Helmand province, told our correspondent that Nato troops would face increased attacks.
"So far, you see just individual suicide attacks. But in the future, you might see as many as six people committing the attacks simultaneously," he said.
"Countless people have enlisted to become suicide bombers. This upsurge is the result of the pressure we are under."
'Regret'
In the clashes in Kandahar, Nato said its forces had used mortar, artillery and air support against large groups of militants who were attacking the alliance's efforts to improve conditions in the area.
Villagers in the Panjwayi region, about 35 km (20 miles) from Kandahar city, told the news agency AFP that about 20 houses had been destroyed and 60 people killed or wounded in fighting.
They said none of the dead were Taleban fighters.
Nato said four civilians wounded in the clashes were being treated at military facilities.
"We deeply regret any civilian casualties caused," the alliance said.
More than 3,000 people have been killed in Afghanistan this year, making it the worst year of violence the country has seen since the Taliban were removed from power by a US-led coalition in 2001.
