Special forces hunt al-Qa'ida in Pakistan

American and British special forces are engaged in a secret war against al-Qa'ida and Taliban fighters who have taken refuge in Pakistan.

The revelation will create acute political difficulties for General Pervez Musharraf, the Pakistani leader, as he faces a referendum in which his support for the West is a focal point for the opposition.

Several US soldiers have been injured in a series of clashes in the mountains straddling the the frontier and inside Pakistan, according to military sources.Yesterday the US forces spokesman at Bagram airbase, north-east of Kabul, refused to confirm or deny that the wounded servicemen had been treated at the airbase.

Members of the British Special Air Service and Special Boat Service also took part in some of the Pakistani operations as observers and intelligence gatherers. The delicacy of General Musharraf's position and Britain's relationship with Pakistan precludes a more aggressive stance, according to diplomatic sources.

In the referendum, due to be held next Tuesday, General Musharraf is seeking to extend his rule by five years. He has sought to sideline members of his own armed forces and the intelligence service, ISI, which helped to create the Taliban, but he is facing considerable opposition from Islamic clerics and parties.

The Pakistani government is said to be deeply alarmed by the propsect of the news of the US operations becoming public. The Pakistani army spokesman, Major General Rashid Qureshi, said: "I think there's some confusion. What I'd heard earlier is that the only thing that may be happening is a communication link. I don't think any Special Forces are operating inside Pakistan." Colonel Rick Thomas, a US Army spokesman , said that "Pakistan has been a staunch ally in the war against terrorism. Beyond that, it is our policy not to iscuss operations". However, the cross-border missions were confirmed by senior US defence sources.

One of the main aims of the campaign is to drive the al-Qa'ida forces back into Afghanistan for the waiting Royal Marines. Brigadier Roger Lane, the Marines commander, has repeatedly stressed that his mandate does not allow cross-border pursuits – a factor exploited by retreating al-Qa'ida troops.

The new policy was launched after the lack of success of assaults by US forces and their Afghan allies at Tora Bora and Shahikot, near Gardez. The Pentagon has been forced to switch from its reliance on technical intelligence gathering and air power to sending in small units of troops to hunt guerrillas operating in small groups.