An American drone strike killed the Pakistani Taliban's number two in North Waziristan, security officials in the region have said, in what would be a major blow in the US fight against militancy.

The drone strike killed seven people, Pakistani security officials said, including Taliban deputy commander Wali-ur-Rehman, in the first such attack since the country's May 11 general election in which the use of the unmanned aircraft was a major issue.

Wali-ur-Rehman had been poised to succeed Hakimullah Mehsud as leader of the Pakistani Taliban, a senior army official based in South Waziristan said in December.

"This is a huge blow to militants and a win in the fight against insurgents," one security official said, declining further comment.

The Pakistani Taliban are a separate entity allied to the Afghan Taliban. Known as the Tehreek-e-Taliban Pakistan (TTP), they have launched devastating attacks against the Pakistani military and civilians.

Pakistani Taliban spokesman Ihsanullah Ihsan said, however, that the group did not have "confirmed reports" that Wali-ur-Rehman had been killed.

Drone casualties are notoriously difficult to verify, with foreign journalists requiring permission from the military to visit the Pashtun tribal areas along the Afghan border. Taliban fighters also often seal off the sites of drone strikes immediately so Pakistani journalists cannot see the victims.

"That the Taliban are remaining silent and neither denying or confirming the news is itself peculiar," said Saleem Safi, a Pakistani expert on the Taliban. "But if this news is true, then the Pakistan army has the US to thank."

The security officials and Pashtun tribesmen in the north-western region said the drone fired two missiles that struck a mud-built house at Chashma village, three kilometres (two miles) east of Miranshah, the region's administrative town. They said seven people were killed and four wounded.

"Tribesmen started rescue work an hour after the attack and recovered seven bodies," said resident Bashir Dawar. "The bodies were badly damaged and beyond recognition."

The Pakistan government had yet to confirm Wali-ur-Rehman's death last night.

Another US drone killed Pakistani Taliban commander Baitullah Mehsud in 2009 and there had been several reports that his successor, Hakimullah Mehsud, was killed the same way but they turned out to be untrue.

The attack led the country's foreign ministry to again denounce drones yesterday. It said: "The government has consistently maintained the drone strikes are counter-productive, entail loss of innocent civilian lives, have human rights and humanitarian implications and violate the principles of national sovereignty, territorial integrity and international law."

US President Barack Obama had recently indicated he was scaling back the drone strike programme, winning cautious approval from Pakistan. That announcement was widely welcomed by people in North Waziristan, where drones have carried out the most strikes over the past seven years, sometimes with heavy civilian casualties.

The strike also coincided with the first session of the newly elected provincial assembly of Khyber Pakhtunkhwa, the former Northwest Frontier Province.

Former cricketer Imran Khan's Pakistan Tehreek-e-Insaf party won most seats in the assembly and denounced the strike, saying Mr Obama had gone back on his word.