Defence revealed yesterday that special forces had found ''senior provincial Taliban extremist commander'' Mullah Akhtar Mohammed, ensured no civilians were nearby and called in an airstrike to kill him in a remote part of Oruzgan province yesterday week.

Brigadier Brian Dawson said Mullah Mohammed had equipped several suicide bombers who had attacked bases in the southern province and controlled a large force of insurgents.

This comes after special forces captured the Taliban's shadow governor for Oruzgan, Mullah Bari Ghul, earlier this month.

The director of the ANU's Centre for Arab and Islamic Studies, Professor Amin Saikal, said Mullah Mohammed was an important target.

''But then again the Taliban have been able to replenish their commanders quite frequently ... Afghan and international forces in Afghanistan have taken out quite a number of Taliban commanders in the past, and that has not necessarily affected operations of the Taliban or the intensity with which they have waged their insurgency.''

Fears are also developing about the impact of Pakistani President Pervez Musharraf's resignation on Afghanistan's fragile state.

Pakistan has been a key ally in the ''war on terror'' but is facing challenges from resurgent Islamic militants in the lawless border areas.

Terror mastermind Osama bin Laden and remnants of al-Qaeda are believed to be hiding in the region, regarded as a safe haven for insurgents conducting attacks in Afghanistan.

Prime Minister Kevin Rudd said the new Government's response was a core concern for countries with troops across the border in Afghanistan, including Australia and its 1080-strong force.

Foreign Minister Stephen Smith said Australia had been worried about Pakistan's stability for some time and it was to be hoped Mr Musharraf's resignation would bring a difficult period to an end.

He said the Federally Administered Tribal Areas were a ''international hotbed of terrorism''. - with AAP