Suspected U.S. drones fired missiles at a vehicle in Pakistan's South Waziristan region on the Afghan border on Thursday, killing five militants, Pakistani intelligence officials said.

The attack could not be independently confirmed. The United States has killed high-profile al Qaeda and Taliban leaders in Pakistan's restive tribal regions with drone strikes.

The latest attack comes nearly a week after U.S. Secretary of State Hillary Clinton visited Islamabad accompanied by high-level U.S. military and intelligence officials.

Clinton again urged Pakistan to eliminate what Washington says are safe havens along its porous border with Afghanistan.

The New America Foundation think tank estimates at least 325 militants were killed in U.S. drone strikes in Pakistan this year.

(Reporting by Hafiz Wazir in Wana and Saud Mehsud in Dera Ismail Khan; Editing by Nick Macfie)