"I don't know exactly where he is but what is clear is that bin Laden is alive, he is in the region," said Zalmai Rasoul, national security advisor to President Hamid Karzai.

"If we knew about his whereabouts, we would've caught him -- but he'll be caught one day," Rasoul told AFP in Parun, the capital of the poverty-stricken northeast province of Nuristan, which borders Pakistan.

A US-led coalition of about 20,000 troops is in Afghanistan hunting the al-Qaeda leader who was sheltered by the hardline Taliban regime that ruled the country until late 2001.