The Taleban diplomat assigned to the United Nations, Abdul Hakeem Mujahid, held a meeting in Washington with the US Assistant Secretary of State, Karl Inderfurth, and said that the Saudi dissident had left last Friday or Saturday.

"He is not in the area under the control of the Taleban," Mr Mujahid told reporters the meeting.

"He decided himself to leave."

The Taleban do not control all of Afghanistan and it was not immediately clear whether Osama bin Laden had left the country entirely, or just the Taleban-controlled areas.

Last weekend, the Teleban announced that it no longer knew the whereabouts of Osama bin Laden, who had been based in the southern Afghan city of Kandahar.

'Taleban won't support terrorism'

US State Department spokesman James Foley said the Taleban had not said where bin Laden was now, or the circumstances of his departure.

"We will continue our efforts to locate him and see that he is brought to justice," he said.

Mr Mujahid told the US the Taleban had placed increasing restrictions on the Saudi-born exile in recent weeks.

"We have been told that the Taleban will not support international terrorism in any form. We hope this will prove true."

The United States has accused Mr Bin Laden of masterminding last year's attacks on the American embassies in Kenya and Tanzania last August.

The United States launched cruise missile attacks against his group in eastern Afghanistan last August in response to the embassy bombings.

The State Department has made clear Washington is prepared to strike again.