A suspected US drone strike killed at least 11 militants Tuesday in Pakistan's tribal region near the Afghan border, an intelligence official said.

Several more people were injured in the aerial strike in the Datta Khel area of the North Waziristan tribal district, a known hub of Islamic militancy.

An intelligence official who spoke on condition of anonymity said four missiles were fired from a drone at two insurgent camps in the mountains.

According to the official, some of those killed were 'foreigners', a term that generally refers to Al-Qaeda-linked militants of Arab or Central Asian origin.

The toll and identities of the victims could not be independently verified as the area is out of reach of the media.

US authorities have intensified drone strikes in the North Waziristan district, which is used by insurgents to launch attacks across the border on NATO forces in Afghanistan.