MIRANSHAH, Pakistan (Reuters) - Rockets fired from a U.S. drone killed 15 people in northwest Pakistan on Monday, intelligence officials said, an attack likely to add to tensions between Washington and Islamabad amid a standoff over NATO supply routes to Afghanistan.

The strike, the third in three days, targeted a militant hideout in the Hesokhel village of the North Waziristan tribal region, officials said.

It brought the death toll from drone attacks in Pakistan in the past three days to 27. Pilotless U.S. drones hit targets in the South Waziristan tribal region on Saturday and Sunday.

The United States and Pakistan are deadlocked in difficult negotiations for the re-opening of overland supply routes to NATO forces in Afghanistan. No breakthrough is in sight.

Islamabad blocked the routes in November 2011 after 24 Pakistani soldiers were killed by cross-border "friendly fire" from NATO aircraft.

The supply lines through Pakistan are considered vital to the planned withdrawal of most foreign combat troops from Afghanistan before the end of 2014.

The Pakistan government says the CIA drone campaign fuels anti-American sentiment in the country, and is counterproductive because of collateral damage.

U.S. officials, however, say such strikes by the remotely piloted aircraft are highly effective against militants and are an important weapon in war against militancy.

(Reporting by Haji Mujtaba in MIRANSHAH, Jibran Ahmad in PESHAWAR and Saud Mehsud in DERA ISMAIL KHAN; Writing by Qasim Nauman; Editing by Paul Tait)