18 killed in suspected U.S. drone attacks in Pakistan

Suspected U.S. drone strikes in Pakistan's tribal region killed 18 alleged militants Tuesday night, intelligence officials told CNN.

Two Pakistani intelligence officials said the suspected drones fired two missiles at different sites in South Waziristan.

South Waziristan is one of the seven districts of Pakistan's volatile tribal region bordering Afghanistan.

The intelligence officials asked not to be named because they were not authorized to speak to the media.

U.S. officials rarely discuss the CIA's drone program in Pakistan, though privately they have said the covert strikes are legal and an effective tactic in the fight against extremists.