At least eight people were killed and four injured in two suspected US drone strikes in Pakistan's northwestern tribal district of North Waziristan Sunday, security officials said.

An unmanned drone aircraft fired three Hellfire guided missiles into a compound in the Alora Mandi area of North Waziristan, a known safe haven of Taliban and Al Qaeda militants launching cross-border raids on NATO-led international forces in Afghanistan.

'The drone attack partly demolished the compound and killed five people. Four more people were injured,' said an intelligence official who spoke on condition of anonymity.

In the second attack, another drone fired two missiles on a vehicle driving through Sanzela area of the district. Three people died, said a second intelligence official who also sought anonymity because he was not authorised to speak to the media.

The US has conducted several dozen airstrikes in North Waziristan and six other districts of Pakistan's tribal region in recent years, killing dozens of top Al Qaeda operatives and Pakistani Taliban leaders.

In his bid to curb the insurgencies, US President Barrack Obama has put special emphasis on the tribal area, described by Washington as the most dangerous place in the world and a hub of global terrorism.

The Pakistani government routinely protests against the US strikes, saying they violate its sovereignty and complicate its efforts against terrorism by fuelling anti-Americanism.

But some analysts believe Pakistani intelligence agencies are assisting the CIA in identifying possible targets.