In a frank interview, Zabiyullah Mujahed, a Taliban spokesman who is believed to be hiding somewhere in southern Afghanistan, admitted that Nato forces had penetrated the Taliban but said the damage was limited.

He added that the Taliban was also recovering from allied attacks that killed some of its leaders.

"I absolutely reject the suggestion that we have been defeated. Our operation continues and gathers momentum day by day," he said, apparently speaking by telephone.

"The enemy has tried to infiltrate the Taliban ranks and has targeted our leadership. Thank God they haven't been too successful. We are trying to catch their spies," he said through an interpreter.

"Unfortunately, some have succeeded. But now we are using counter-intelligence to find these people," he added.

The spokesman also admitted that a suicide bombing in Kabul on Sunday that killed 35 people, the deadliest of the Taliban insurgency, demonstrated a new approach, including the use of suicide bombers.

"With each passing day, taking into account the enemy's tactics, we are changing our own tactics," he said.

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

"This is our next main target. Probably we will be successful."

"Our enemy is the same and we are repeating the tactics which they use in Iraq. They have proved effective in defeating the enemy," he added. "Our goal is the same -- the independence and freedom of our country."

The spokesman said they were not lacking in volunteers -- and if anything, the numbers were growing.

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