US drone strikes on Monday killed 15 militants in Pakistan's tribal district of South Waziristan, destroying compounds in twin attacks just minutes apart, local security officials said.
The first strike killed seven militants in the early hours in Shalam Raghzai, 10 kilometres (six miles) northwest of Wana, the district's main town.
A second slammed two missiles into a compound in the Wacha Dana area, 12 kilometres northwest of Wana, Pakistani officials said.
"At least eight militants were killed when a US drone fired two missiles on a compound," a senior security official told AFP of the second attack.
Officials said initial reports suggested that some foreign militants may have been killed in the first attack and that Pakistani Taliban were targeted in the second strike, which came just 15 minutes later.
The first strike targeted a compound near a madrassa just south of the Ghwakhwa area, where senior Al-Qaeda commander Ilyas Kashmiri, one of the network's most feared operational leaders, was reportedly killed days earlier.
Kashmiri has a US bounty of $5 million on his head. Pakistani officials said he was the target of a Friday drone strike in which nine members of his outlawed Harakat-ul-Jihad al-Islam (HuJI) group died.
The 47-year-old has been blamed for high-profile attacks on Western targets, accused over the November 2008 attacks on India's financial capital Mumbai and for masterminding devastating attacks on Pakistan's military.
Washington has called Pakistan's semi-autonomous northwest tribal region the most dangerous place on earth and the global headquarters of Al-Qaeda. Taliban and other Al-Qaeda-linked networks have carved out strongholds there.
Although the United States does not confirm Predator drone attacks, its military and the CIA operating in Afghanistan are the only forces that deploy the armed, unmanned aircraft in the region.
Monday's strikes were the 10th and 11th to be reported in Pakistan's tribal areas since US commandos killed Al-Qaeda founder Osama bin Laden in a raid in the Pakistani garrison city of Abbottabad on May 2.
Pakistan's parliament has called for an end to the US missile attacks and demanded no repeat of the operation that killed bin Laden, despite President Barack Obama saying he reserves the right to act again.
Pakistan is on the frontline of the US-led war on the Taliban and Al-Qaeda, and bomb attacks across the country have killed more than 4,400 people in the last four years -- blamed on militants opposed to the government's US alliance.
On Sunday, at least 24 people were killed in two separate bombings in the northwest -- the first at a bus terminal near the city of Peshawar killing six people and the second killing 18 at a bakery in the garrison town of Nowshera.
The bin Laden raid profoundly jolted Pakistan's security establishment, with its intelligence services and military widely accused of incompetence or complicity over the presence of bin Laden close to a military academy.
The drone strikes are hugely unpopular among the general public, who are deeply opposed to the government's alliance with Washington, and inflame anti-US feeling, which has surged further after the bin Laden raid.
But US officials say the missile strikes have severely weakened Al-Qaeda's leadership and killed high-value targets including the former Pakistani Taliban chief Baitullah Mehsud.
Missile attacks doubled in the area last year, with more than 100 drone strikes killing over 670 people, compared with 45 strikes that killed 420 in 2009, according to an AFP tally.
Most of the attacks have been concentrated in North Waziristan, the most notorious Afghan Taliban and Al-Qaeda bastion in Pakistan, where the United States wants Pakistan to launch a ground offensive as soon as possible.