I don't know what purpose would be served right now, since the position of the United States and the international community is quite clear

US Secretary of State Colin Powell

Mr Jackson said he had been invited by the Taleban to act as a mediator over US demands that Afghanistan hand over Osama Bin Laden.

But the Taleban's representative in Pakistan, Mullah Abdul Salaam Zaeef, said it was Mr Jackson himself who had made the mediation offer.

Mr Jackson said the Taleban wanted him to mediate peace with the regime accused of harbouring Osama Bin Laden, who the US suspects of involvement with the terror attacks on New York and Washington on 11 September.

He also said he had received a personal appeal from the parents of two Americans being held in Afghanistan on charges of preaching Christianity.

More information

He said he needed more information before he made his final decision.

But Secretary of State Colin Powell said: "We have nothing to negotiate, they know what our position is."

Mr Powell stressed that Washington would not move to stop Mr Jackson from travelling to Afghanistan but said he did not see the point of going.

"He is free to travel," Mr Powell said. "I don't know what purpose would be served right now, since the position of the United States and the international community is quite clear."

Mr Jackson announced that he had been invited by the Taleban on Thursday.

The Taleban initially denied they had issued an invitation to Mr Jackson, but said they would welcome his offer to travel to Afghanistan for talks on the Bin Laden situation.

Any such discussion would be Reverend Jackson's own initiative or decision, he would not be carrying a message from the United States

State Department spokesman Richard Boucher

But even as Mr Jackson made his initial announcement, US officials played down the proposal.

Deputy Secretary of State Richard Armitage said: "We're not interested in a dialogue.

"We're interested in action and no negotiation. The demands are not subject to dialogue."

Mr Powell and Mr Armitage said the demands were "not negotiable" and that if the militia wanted to avoid possible retaliatory strikes it must hand over Bin Laden and eliminate his al-Qaeda network.

Mr Armitage said the Taleban appeared to be stalling on turning over Bin Laden.

"It seems to me they're trying to delay making a decision on their own," Mr Armitage said.

On his own

State Department spokesman Richard Boucher went further than both Mr Powell or Mr Armitage, saying that if Jackson went, he would be totally on his own.

"He'll have to make his own decision about talking with the Taleban," Mr Boucher told reporters.

"Any such discussion would be Reverend Jackson's own initiative or decision, he would not be carrying a message from the United States."

Reverend Jackson is no stranger to international conflict.

He negotiated the release of captured American servicemen in the Balkans two years ago and served as President Clinton's special envoy to Africa.