US drone strikes in Pakistan hours after sovereignty pledge

A US drone attacked suspected militants inside Pakistan yesterday, only hours after the US military chief assured Pakistani leaders that the country's sovereignty would be respected.

In an effort to calm escalating tensions between Washington and Islamabad, the chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, made a surprise visit to the Pakistani capital after it emerged that President George Bush had authorised US forces to attack Taliban militants in tribal areas on the border between Afghanistan and Pakistan.

The two allies have been locked in a game of brinkmanship since US special operations troops mounted the first known ground assault in Pakistan, allegedly killing up to 20 people in a village in South Waziristan. Afterwards Pakistan's army vowed to retaliate and defend itself "at all costs".

Admiral Mullen met Prime Minister Yousaf Raza Gilani and the Pakistani army chief General Ashaf Kayani. Afterwards the US embassy said: "Admiral Mullen reiterated the US commitment to respect Pakistan's sovereignty and to develop further... co-operation."

But within hours a pilotless drone fired four missiles into South Waziristan, killing five militants, according to local intelligence officials. Reuters claimed the attack was the product of "US-Pakistani intelligence-sharing", but government officials appeared to disagree.

"The [Mullen] visit was nice and he was very understanding," said Ahmad Mukthar, the Defence minister. "Now these airstrikes have come as a surprise."

The new civilian Pakistani government is fearful that increased US intervention will inflame an already hostile public. On Tuesday, President Asif Ali Zardari urged Gordon Brown to persuade the Americans to relent during a meeting at Downing Street.

"The UK agrees with us that such moves are counterproductive," said an official. "Britain has a major role to play [here] – they know the area better than the US."