Bush says he was 'taken aback' by Musharraf's bombing claim

President George Bush has said he was "taken aback" by an alleged threat by a former official to bomb Pakistan "back to the Stone Age" if it did not co-operate after the September 11 attacks.

"I guess I was taken aback by the harshness of the words," Mr Bush said, as he stood alongside Pakistan's President Pervez Musharraf at the White House yesterday, in what was intended as a strong show of unity between the US and Pakistan.

However, the summit served to underline the edginess between the two countries, which began with Washington's evident surprise at the recent peace treaty between the Pakistan government and tribes in Waziristan along the Afghan-Pakistan border. Critics here say the deal amounts to a tacit endorsement of the Taliban and sanctuary for Taliban leaders and Osama bin Laden, who are believed to be hiding in the region.

However, Mr Musharraf insisted the treaty was not meant to support the Taliban. "This deal is against the Taliban," he said. "This deal is with the tribal elders." Mr Bush added: "I believe him."

The US President had, however, stoked a separate dispute in a CNN interview earlier this week, in which he declared he would "absolutely" send US troops into Pakistani territory to capture or kill Bin Laden if he had intelligence that the al-Qa'ida leader was there. Mr Musharraf took exception to this, saying his forces were perfectly capable of doing the job.

Finally there has been Mr Musharraf's claim, on a CBS television programme to be broadcast tomorrow, that after the September 2001 attacks the then deputy secretary of state, Richard Armitage, had told Pakistan's intelligence director that the US would bomb his country if it did not throw in its lot with Washington. He said Mr Armitage had warned him: "Be prepared to go back to the Stone Age."

Mr Armitage denied using that phrase. He admitted, however, that he had delivered a forceful message, with words to the effect of: "Either you are with us or against us. History begins now." The Pakistani leader described the Stone Age comment as "a very rude remark".

At the White House yesterday, Mr Musharraf declined to elaborate, citing an agreement with the publishers of a book that is due out next week. "I guess he's saying, 'buy the book'," Mr Bush joked.

But neither such bonhomie nor the praise heaped by the US President on his guest for his commitment to fight terrorism, could mask the tensions. Mr Musharraf proclaimed anew his determination to bring al-Qa'ida leaders to justice, but seemed less relaxed than at previous appearances with Mr Bush.

The US President will hold talks with Hamid Karzai, the Afghan President, on Tuesday before a three-way meeting with Mr Karzai and Mr Musharraf at the White House the next day, at which the fight against the Taliban and al-Qa'ida will top the agenda. "We are in the hunt together against these people," the Pakistani leader said. He also claimed progress toward a settlement of the decades-old dispute with India over the Kashmir region. "We are moving on the Kashmir dispute," he said, referring to recent talks with the Indian Prime Minister, Manmohan Singh.

The summit between Mr Bush and Mr Musharraf came less than 24 hours after the White House and rebel Republicans in the Senate reached a compromise on a bill setting out procedures to interrogate and try terrorist suspects.

Yesterday both sides were claiming victory, with the administration insisting it now had the tools it needed to protect the population, while the senators claimed that the deal did not involve any change in the existing Geneva protocols governing the treatment of prisoners of war.