A suspected U.S. drone fired a missile at a Taliban target in Pakistan's North Waziristan tribal region on Monday, killing at least four militants, intelligence officials and residents said, Reuters reported.
Pakistani Taliban chief, Baitullah Mehsud, was killed in a similar attack in the neighboring South Waziristan region last month.
The latest attack took place near Mir Ali, the second major town of North Waziristan and a sanctuary for militants linked to al Qaeda and the Taliban.
The blast was so huge that it could be heard as far as Miranshah, the main town of the sparsely-populated region, which is about 24 km (15 miles) from Mir Ali.
Akhtar Rasool, a resident of Mir Ali, said the missile appeared to have struck a militant vehicle.
"The vehicles is in flames and we can see smoke rising from the scene," he told Reuters by telephone.
An intelligence official said at least four militants were killed and that the death toll may rise.
He said the militants appeared to be foreigners.
The strike came a day after the government said the top Taliban leader in the troubled Swat region, Fazlullah, had been surrounded and would soon be captured.
Pakistan officially objects to the U.S. missile strikes saying they are a violation of its sovereignty and cause civilian casualties, which bolster Islamist support. But local media reports have suggested that the strike that killed Mehsud was carried out with Islamabad's coordination.
Facing surging violence in neighboring Afghanistan, the United States stepped up its missile strikes in Pakistan last year, killing hundreds of militants.
Pakistani and U.S. officials said the militants were in disarray after Baitullah's death and their attacks appeared to tail off.
Attacks by the Pakistani Taliban early this year raised fears over the stability of the nuclear-armed nation but the Islamist militants have suffered a series of setbacks in recent weeks including the killing of Mehsud.
Last week, the security forces said they had captured five Taliban leaders, including the top spokesman for the militants in the Swat valley.
Security forces launched an offensive in the Swat, about 120 km (80 miles) northwest of Islamabad, in late April and killed more than 2,000 fighters, according to the army.
The security forces this month launched an operation in Khyber, a tribal region and the main route for fuel and food supplies to the Western forces in Afghanistan, and have so far killed nearly 150 militants, officials say. There has been no independent verification of that casualty estimate.