At least two suspected foreign militants were killed in a U.S. drone strike in Pakistan's volatile border region of North Waziristan, local officials said on Sunday.
Drones armed with missiles have inflicted the most damage against Taliban fighters in Pakistan's lawless tribal areas straddling the Afghan border over the past seven years, sometimes with heavy civilian casualties.
In the third drone attack since Pakistani Prime Minister Nawaz Sharif took office last month, two people riding a motorcycle were struck by missiles in the Mir Ali area of North Waziristan on Saturday night, one official said.
"The two men, probably Arab nationals, were passing through Mosaki village when the drone fired two missiles and hit them," said the official.
Their identities were not immediately known. The official in Mir Ali said they were Arabs, but another security source in the region told Reuters they were foreign militants of Turkmen origin.
U.S. drone attacks began in Pakistan in 2004. It has been difficult to check their impact on both militants and civilians because independent observers and journalists have almost no access to the areas where most of the strikes occur.
Pakistani Taliban fighters, who operate as a separate entity but are allied with their Afghan counterparts, often seal off the sites of drone strikes immediately.
Pakistan's government has denounced the attacks as a violation of its sovereignty. U.S. President Barack Obama has promised to scale them back, resorting to them only when a threat was "continuing and imminent".