Pakistani intelligence officials say a suspected U.S. drone strike has killed five militants linked to a top Taliban commander in Pakistan's northwest tribal region.

The officials said the unmanned aircraft fired missiles Thursday at a vehicle in the town of Azam Warsak in South Waziristan, killing a senior leader and four other militants led by Maulvi Nazir.

Nazir's fighters are said to cross the border to attack U.S. and NATO troops in neighboring Afghanistan.

Officials said the drone strike also killed Nazir's younger brother.

In June, missile strikes killed 15 militants believed to be allied with Nazir, and in May his followers threatened to carry out revenge attacks against Pakistan and the United States for the U.S. killing of al-Qaida leader Osama bin Laden.

The United States does not publicly acknowledge the use of drone strikes against Taliban and al-Qaida-linked militants in Pakistan's northwest. Pakistani officials have protested the attacks as a violation of the country's sovereignty.

Also Thursday, police said a bomb exploded in a popular market in Peshawar, wounding at least seven people.

Authorities said the explosives were packed in an oil canister.

No one immediately claimed responsibility for the blast, which damaged several nearby shops.

Peshawar is the capital of Khyber-Pakhtunkhwa province near the Afghan border, and has experienced numerous suicide and bomb attacks in recent years linked to the Taliban and al-Qaida.