Leaders of the Northern Alliance, exuberant after the capture of Mazar-e-Sharif and Herat, said yesterday they planned to advance on the Taliban stronghold of Kandahar in the south - a prospect with wide-ranging implications for American diploma tic and military strategy.
Western officials said last night the claims may be designed primarily to put psychological pressure on the Taliban. However, there were reports - again from the Alliance - that Taliban fighters were leaving Kabul for Kandahar to defend the city.
An anti-Taliban warlord in southwest Afghanistan said his forces had captured the strategic town of Zaranj near the Iranian border.
"We have captured the city. The Taliban resisted for half an hour but then ran away towards Hirmand and Kandahar," Mr Abdolkarim Barahui said.
The US has been pinning its hopes on Pashtun tribal leaders to defect away from the Taliban and form a southern alliance force supported by American special forces and ground troops.
Senior American officials said the key to defeating the Taliban had now shifted to the south.
"We're having some battlefield victories, the Northern Alliance is," the American defence secretary, Mr Donald Rumsfeld, said on Sunday. "And now it's time for the southern tribes to get active." A senior Bush administration official was quoted in the New York Times as saying: "There is a great risk if the war is seen as a struggle between the United States and the Pashtun. But so far the southern strategy has not gone well."
A prominent Pashtun tribal leader, Mr Ahmed Karzai, claimed yesterday that the Northern Alliance's capture of towns in the north and west had made his job of forging an anti-Taliban alliance in central and southern Afghanistan much easier.
Mr Karzai said he was talking to other tribal leaders from a large area of central and southern Afghanistan and even from a pocket in the east.
The US also does not want the Northern Alliance - a collection of warlords not known for their magnanimity in victory - to increase its control over Afghan territory.
Hundreds of pro-Taliban Pakistani fighters are reported to have been systematically massacred in Mazar-e-Sharif after being abandoned by retreating Taliban fighters. The Taliban soldiers fled from Mazar four days ago but failed to inform a contingent of up to 1,200 Pakistani jihadis that they were leaving.
American military commanders are wrestling with plans to deploy larger numbers of airborne troops to attack Taliban positions, a task which in the present state of uncertainty and lack of good intelligence would be an extremely risky tactic. This would be even more the case if the Taliban chooses to concentrate its forces in the south, including Kandahar.
It is likely that the US will switch its bombing priorities from the north - where Taliban positions have accounted for 80 per cent of air strikes over the past week - to the south.
US war planes, which stopped bombing the Taliban's front lines shortly before the opposition offensive began around midday, redirected their efforts to Taliban targets in the capital itself.
Three bombs struck shortly after dusk and witnesses reported that one partially destroyed the house of the Taliban's governor for Kabul, Mullah Abdul Manan Niazi. No casualties were reported.
A Northern Alliance spokesman, Mr Waisudin Salik, said the Taliban abandoned their positions north of Kabul in the face of a two-pronged advance by 7,000-8,000 opposition soldiers seeking the biggest prize of their campaign. The alliance forces were almost completely in control of the Shomali plain outside Kabul and "there are no major obstacles remaining in front of us", Mr Salik said. Defeat of the Taliban in Kabul would be a huge symbolic victory for the US-led drive to topple the regime for harbouring Osama bin Laden, suspected mastermind of the September 11th terror attacks on the United States.