PESHAWAR, Pakistan – A bomb killed seven Pakistani soldiers and wounded 11 others Saturday, officials said after US Secretary of State Hillary Clinton warned Al-Qaeda is at the core of the country's terrorist threat.

"Seven paramilitary soldiers were killed and 11 were wounded in the remote-control bomb attack," Shafirullah Khan, the top administrative official in the northwestern tribal district of Khyber, told AFP by telephone.

The Frontier Corps later issued a statement confirming that seven of its members had "embraced martyrdom". It gave their names and said they died in an improvised explosive device blast.

Military and security officials in nearby Peshawar city said two vehicles carrying rations for Pakistani troops were destroyed in the explosion, which occurred about 15 kilometres (nine miles) west of Peshawar.

The military launched an offensive in Khyber, home to the Khyber pass into neighbouring Afghanistan, on September 1 after a suicide bomber blew himself up near a border post. That attack killed 22 policemen.

The semi-autonomous northwest tribal belt has become a stronghold for extremists who fled Afghanistan after a US-led invasion toppled the hardline Islamic Taliban regime there in late 2001.

Officials on Saturday blamed local militants for the attack on the soldiers. They were not specific but Lashkar-e-Islam is the main militant group fighting in that area.

The group has ties to the Pakistani Taliban headquartered further south in the semi-autonomous district of South Waziristan, where government forces on October 17 began a separate major offensive aimed at rooting out "terrorists".

Around 30,000 troops are taking part in the South Waziristan campaign against an estimated 10,000-12,000 militants.

The military said Saturday that troops killed 33 insurgents but faced mortar fire and street battles as they pressed their offensive.

No information provided by the army can be verified because communication lines are down and journalists and aid workers are barred from access to the area on the wild Afghan border.

The latest casualties reported bring to 297 the total number of insurgents reported killed since the operation started.

Relief workers say more than 200,000 people have been displaced by the fighting.

Numerous previous offensives in the tribal belt have had limited success, costing the lives of 2,000 troops and ending generally with peace agreements that critics say gave the insurgents a chance to re-arm.

At the end of a visit to Pakistan on Friday, Clinton hit out at Pakistan's silence on the whereabouts of Al-Qaeda leaders.

"We don't know where and I have no information that they know where but this is a big government. You know, it's a government on many levels. Somebody, somewhere in Pakistan must know where these people are," Clinton said.

"And we'd like to know because we view them as really at the core of the terrorist threat that threatens Pakistan, threatens Afghanistan, threatens us, threatens people all over the world," she told radio journalists.

"I think it is absolutely clear and I am convinced that you will never rid Pakistan of the threat of terrorism unless you rid it of Al-Qaeda," Clinton said.

Her visit was overshadowed by the country's second-worst bomb attack.

Hopes of pulling more bodies from the scene of the Meena market car bombing all but disappeared on Saturday.

The top official in Peshawar said there was little chance of recovering the remains of 16 people listed as missing after Wednesday's attack, in which 118 have been confirmed killed.

Still, relatives continued to shuttle between the hospital and the bomb site hoping to locate their loved ones.

"I know they are dead but can somebody tell me where I can find their bodies?" said Waqar Ahmad, weeping as he held photographs of his mother and father.

The attack underscored the gravity of Islamist attacks that have killed around 2,400 people in two years and are seen by most Pakistanis as part of a backlash against the government's alliance with the United States.