The Taleban in Afghanistan are changing their tactics to mount more attacks on the capital, Kabul, a spokesman for the militant group has told the BBC.

The spokesman, Zabiyullah Mujahed, said Taleban were recovering after Nato had infiltrated the group and killed some of its leaders.

But more people were volunteering to carry out suicide bombings, he said.

A police bus in Kabul was bombed on Sunday killing up to 35 people, in the deadliest attack there since 2001.

Mr Mujahed said the city was the next main target of the Taleban.

"It is true we are increasing our pressure on Kabul, because Kabul is the capital city and the foreign troops are concentrated there," Zabiyullah Mujahed said.

He added that the "independence and freedom of our country" was the goal of the Taleban and that they were repeating the same tactics used by insurgents in Iraq.

"A lot of people are coming to our suicide bombing centre to volunteer," he said.

'Tide turning'

On Wednesday Afghan Defense Minister Abdul Rahim Wardak said support for the Taleban was diminishing.

"At the moment you see the tides are turning in our favor, the Taleban have failed to materialize their so called spring offensive, they have failed to isolate Kabul or to cut highways or to expand their area of influence," he told the BBC.

Despite the Taleban's new focus on the capital city, heavy fighting in the south of the country has continued.

Three Canadian Nato soldiers were killed by a roadside bomb in Kandahar province on Wednesday.

The Taleban said it had carried out the attack.

About 90 foreign troops have been killed in Afghanistan this year, most in combat for the Nato-led force Isaf in the country's south.

Correspondents say that the south of the country has this year seen the worst violence since the Taleban were ousted from power in 2001 by an international coalition.

PHOTO CAPTION

Afghan policeman in Kabul