UPDATE 2-U.S. drone attack kills at least five in Pakistan

(For a related FACTBOX, double click on [ID:nISL402585])

(Adds casualties)

ISLAMABAD May 9 (Reuters) - Missiles fired by suspected pilotless U.S. drone aircraft struck a compound in a Pakistani region on the Afghan border on Saturday, killing at least five militants, intelligence and Taliban officials said.

Four missiles fired by two drones hit a compound in Sarorogha village in the South Waziristan tribal region, a stronghold of Pakistani Taliban leader Baitullah Mehsud and a known al Qaeda and Taliban hotbed, one of the intelligence officials said.

"We have reports of at least five militants killed in the missile attack," said the official. The same figure was given by a Taliban official in the region.

Another intelligence official put the death toll at as high as 20, and said one of the missiles also hit a vehicle carrying militants.

The United States began increasing the frequency of drone attacks in Pakistan a year ago. There has been no let-up since President Barack Obama's administration took office in January, despite complaints from the Pakistani government.

The United States carried out about 40 drone air strikes since the begining of last year, most since September, killing more than 300 people, according to a tally of reports from Pakistani intelligence agents, district government officials and residents.

Including Saturday's strike, there have been 15 attacks this year, with five in April. (For other stories on Pakistan and Afghanistan double click on [ID:nSP102615]) (Reporting by Alamgir Bitani; Writing by Augustine Anthony; Editing by Jerry Norton and Paul Tait)