US missiles killed 15 militants in Pakistan's northwestern tribal belt where the United Nations announced on Monday it was suspending food handouts in one district after a suicide attack.
The missiles destroyed a vehicle and compound in North Waziristan, probably the country's most impregnable Taliban and Al-Qaeda fortress where US officials want Pakistan to launch a ground offensive to obliterate the militant threat.
Local security officials said unmanned US aircraft fired at least six missiles at the targets in Mir Ali village, 25 kilometres (16 miles) east of Miranshah, the tribal district's main town.
The identities of the dead were not immediately clear, but officials believed that most of them were Pakistani, rather than Afghan or Arab fighters. The Mir Ali area is believed to be a Pakistani Taliban stronghold.
"At least 15 militants were killed in a US missile strike, which targeted a vehicle and a compound," a senior Pakistani security official told AFP.
"Four missiles hit the vehicle and two struck the compound," he added. Security officials had initially put the death toll at six.
Washington says eliminating the militant threat in Pakistan's semi-autonomous tribal belt is vital to winning the nine-year war against the Taliban in neighbouring Afghanistan and defeating Al-Qaeda.
The United States does not confirm drone attacks, but its military and the Central Intelligence Agency operating in Afghanistan are the only forces that deploy the aircraft in the region.
The covert campaign has doubled missile attacks in the tribal area this year where around 100 drone strikes have killed more than 640 people since January 1, compared to 45 killing 420 people in 2009, according to an AFP tally.
Pakistan tacitly cooperates with the bombing campaign, which US officials say has severely weakened Al-Qaeda's leadership, but has stalled on launching an offensive in North Waziristan, saying its troops are too overstretched.
The United Nations said Monday it had suspended food handouts in Bajaur, which like North Waziristan is one of seven districts in the tribal belt, after 43 people were killed in Pakistan's first female suicide bombing.
The decision affects nearly 300,000 people who depend on general rations from the World Food Programme (WFP) after being affected by years of fighting between Pakistani soldiers and homegrown Taliban militants.
The Taliban claimed responsibility for Saturday's attack in part of Pakistan's semi-autonomous tribal belt, which Washington considers Al-Qaeda's chief global nexus and is subject to a covert American drone campaign.
"WFP has temporarily suspended food distribution in Bajaur following the attack at a police checkpoint several hundred metres away from WFP's food distribution point," spokeswoman Jackie Dent told AFP.
"We are talking with the district authorities and hoping to resume the distribution as soon as possible."
WFP has this year provided assistance to an estimated 2.6 million people in the northwest who have left their homes, come back trying to rebuild their lives afterwards or are affected by systemic violence in the northwest.
The agency also provides rations to approximately 294,000 internally displaced people in Bajaur, where the Pakistani military has been fighting against homegrown Taliban militants since August 2008.
Pakistan has repeatedly claimed it has eliminated the militant threat in Bajaur, but the suicide bombing highlighted the prevailing insecurity.
The United Nations said Secretary General Ban Ki-moon was "appalled" by the "abhorrent act of terrorism aimed at innocent people".
US President Barack Obama said killing civilians outside a WFP distribution point was "an affront to the people of Pakistan and to all humanity".
Around 4,000 people have died in suicide and bomb attacks across Pakistan since government forces raided an extremist mosque in Islamabad in 2007. The attacks have been blamed on networks linked to the Taliban and Al-Qaeda.