The Taliban rulers of Afghanistan have said they have mobilised "hundreds of thousands" of troops to repel US strikes on the country as neighbouring Pakistan pulled its diplomats out of the country.

The developments came as a team of senior US defence department officials met counterparts in Islamabad to hammer out Pakistan's exact role in the expected US military operation.

The talks focused on the extent to which Pakistan's military rulers, whose sensitivity to popular opinion has led them to object to any "visible US military presence" on their territory, would provide logistical support to any US ground force in Afghanistan.

Early on Tuesday there were reports that the Saudi Arabian government had severed all relations with the Taliban.

On Monday, A pan-Arab television station quoted Osama bin Laden, the Afghanistan-based fugitive accused of planning the September 11 attacks, as inciting Pakistanis to fight the US.

A statement sent to Qatar-based TV channel al-Jazeera, purporting to be from Mr bin Laden, called on Pakistanis not to assist the "American crusaders". Pakistani officials said they doubted the statement's authenticity.

The Taliban says it has 40,000 regular troops but its ability to call up thousands more was viewed sceptically by some specialists.

In Moscow, President Vladimir Putin offered to create an air corridor over Russia to allow access by US forces to Afghanistan. But he stressed it should be used only for humanitarian aid.

Mr Putin ruled out any direct Russian military involvement in Afghanistan, while stressing his "political and moral support" for a campaign against the ruling Taliban and offering help to the opposition Northern Alliance.

US president George W. Bush yesterday praised Mr Putin, with whom he talked for almost an hour on Saturday.

Mr Bush said that when the US put forces on high alert on September 11 Mr Putin helped avert tensions by not activating Russian forces.

"Vladimir Putin clearly understands that the cold war is over and that the United States and Russia can co-operate. We can co-operate with a new strategic arrangement. We can co-operate in the battle against terrorism," he said.

Turkmenistan and Kazakhstan both said they would be willing to host US bases and aircraft on their soil. Turkmenistan said it would only permit humanitarian missions. Reports from Uzbekistan at the weekend said a US military presence was already moving into position.