Disheartened by an escalating crisis, Pakistani Muslim clerics said Wednesday they had canceled plans to visit the headquarters of Afghanistan's ruling militia, the latest signal that options may be running out for the Taliban.

Even as their isolation grew, though, Taliban leaders accused of sheltering terrorism suspect Usama bin Laden told the world — in English — that they were prepared to negotiate and didn't want war.

Leaders of four major pro-Taliban Islamic parties had planned to travel to the militia's headquarters in the southern Afghan city of Kandahar to meet leader Mullah Mohammed Omar, according to Ameerul Azeem, a spokesman for one of the parties, the Jamaat-e-Islami, or Islamic Party.

The trip was called off because the clerics simply saw no chance of a breakthrough, Azeem told The Associated Press by telephone from Lahore.

Diplomatic pressure on the Taliban is increasing as the United States marshals military forces for probable attacks on Afghanistan, where bin Laden, top suspect in the Sept. 11 terrorist attacks on the United States, is believed to be hiding.

At the same time, the international coalition backing the fight against terrorism is shoring up its support. British Prime Minister Tony Blair scheduled a trip to Pakistan on Friday, according to a senior Pakistani official who spoke on condition of anonymity.

Pakistan, Afghanistan's eastern neighbor and the only country that still recognizes the rigorously Islamic Taliban leadership, is caught in a volatile situation. It supported the Taliban until recently, but agreed after the attacks to assist the United States in fighting terrorism.

In the process, most economic sanctions against Pakistan have been lifted, but President Gen. Pervez Musharraf's government has alienated more extreme segments of its largely Muslim population, causing protests in some cities.

U.S. Deputy Secretary of State Richard Armitage said Washington does recognize the fragility of Pakistan's situation. "We don't want to burden Pakistan with more than we absolutely need," he told ABC's Good Morning America. "We'll be guided by President Musharraf and his views of the political situation in his country."

"I think most of us have been quite heartened that the anti-American activity in Pakistan has been relatively low," he said. The great majority of Pakistanis "want their future to be with the West."

Pakistan's Foreign Ministry said Wednesday it was reviewing information on the U.S. investigation given it by Washington. "Today we received some information, and it is being studied," spokesman Mohammed Riaz Khan said. On Tuesday, the U.S. ambassador briefed Musharraf about the investigation of the attacks.

Blair, who has promised to back any U.S. efforts fully, told a Labor Party conference in Brighton, England, on Tuesday that the Taliban must "surrender the terrorists or surrender power."

In the southwestern Pakistani city of Quetta, where support for the Taliban runs high, the militia's ambassador to Pakistan reiterated his government's refusal to turn over bin Laden without proof.

But Ambassador Abdul Salam Zaeef said the Taliban would be willing to talk — and that they do not want war.

"We are ready for negotiations," Zaeef said in a hastily called news conference. "It is up to the other side to agree or not. Only the way of negotiation will solve our problems."

Zaeef's comments represented no departure from previous statements. But the way they were delivered, in English, rather than the usual statements translated from the Afghan language of Pashtu, seemed aimed at reaching the outside world more directly. 

The United States has turned down Taliban offers to talk. President Bush has told the Taliban to shut down bin Laden's Al Qaeda network in Afghanistan or face the consequences.

Bush has also approved assistance to groups within Afghanistan that oppose the Taliban.

Pakistan is keeping up pressure on its neighbor. Pakistani officials have sent several delegations to Afghanistan to persuade the Taliban to surrender bin Laden; all have been unsuccessful.

"Pakistan has conveyed to the Taliban what the situation is, what are the dangers, what the international community is expecting them to do," Foreign Ministry spokesman Riaz Mohammed Khan said in Islamabad. "We have told them they don't have much time."

The Taliban are also facing pressure from the northern alliance of Afghan groups fighting their regime. Opposition spokesman Mohammed Habil said Wednesday that northern alliance forces had advanced about 8 miles in the central province of Ghor. There was no immediate confirmation by the Taliban.

Much further north, Russian border guards in Tajikistan reported fighting inside Afghanistan between Taliban and opposition forces about 120 miles south of Dushanbe, the Tajik capital.

Another northern alliance spokesman said Wednesday his forces are expecting arms deliveries from Russia and Iran — and humanitarian aid for refugees fleeing Taliban-controlled areas.

The spokesman, Abdullah, who uses only one name, said alliance representatives were having "regular and daily meetings" with U.S. officials outside Afghanistan. He wouldn't elaborate.