The party of Asif Ali Zardari, the widower of slain ex-Prime Minister Benazir Bhutto, has sought to assure the US since Pervez Musharraf's ouster as president that it is committed to battling terrorists.

The country has been hit by a string of suicide bombings this month, including one last week that left 67 dead, many of them civilians.

Prime Minister Yousaf Raza Gilani told reporters Friday that Mr Zardari - who is widely expected to win a Sept 6 presidential election by lawmakers - was staying at a hilltop mansion in Islamabad's government quarters 'for security reasons.'

He did not elaborate, but an intelligence official said there had been reports that the presidential hopeful could be the target of an attack and that he had switched locations after Mr Musharraf's Aug 18 resignation.

The official spoke on condition of anonymity because of the sensitivity of the subject.

Pakistan's 5-month-old civilian government initially sought to calm militant violence by holding peace talks, something Mr Musharraf briefly tried as well.

But it has increasingly intensified military action against Al-Qaeda- and Taliban-linked militants in the northwest, especially in the tribal regions along the Afghan border - a rumoured hideout of Osama bin Laden.

Late Friday, several militants were reported killed in the Swat Valley area, a one-time tourist destination that has been besieged by insurgents.

Major Nasir Ali, a military spokesman, did not have an exact death toll but said it was in the double digits.

Taliban spokesman Muslim Khan said eight militants, including a local commander, had died.

Militants have threatened more suicide bombings unless the operations cease. They have hit one of the country's largest military installations, a hospital and a police station in the last week.

Paramilitary troops foiled a suicide attack in the northwestern region of Kohat on Friday. Four civilians were killed and 28 people, most of them security forces, were wounded when troops fired on an explosive-laden car that had sped through a checkpoint, said Mr Rasheed Khan, a government official.

Suspected militants also blew up two bridges in the area, said Kohat district administrator Mohammad Siraj Khan. -- AP