Islamabad - US pilotless aircraft are believed to have fired two missiles in Pakistan's tribal region bordering Afghanistan on Monday, killing at least seven people, an intelligence official said.

The missiles targeted two vehicles carrying Islamic militants who were firing on the drone with anti-aircraft guns in two different areas of South Waziristan tribal district, a known sanctuary for Taliban and al-Qaeda fighters.

The first strike took place in Kari Khel area, some 15 kilometres south of district's main town of Wana.

"The missile completely destroyed the four-wheel drive and three people were killed. All of them were local Taliban," said an intelligence officer who spoke on condition of anonymity.

The second vehicle was destroyed in Sheen Warsak area. "Four people died there. Among them was a civilian motorcyclist who was passing by the vehicle when the missile hit it," the official added.

In recent months US forces have carried out several drone attacks on suspected hideouts of Taliban and al-Qaeda militants launching cross-border attacks on international forces in Afghanistan.

Though the strikes have eliminated several al-Qaeda operatives, the Pakistani government has condemned them, saying they violate its sovereignty. (dpa)