By Yeganeh Torbati and David Alexander
WASHINGTON (Reuters) - Two U.S. B52 strategic bombers flew near artificial Chinese-built islands in the South China Sea this week and were contacted by Chinese ground controllers but continued their mission undeterred, the Pentagon said on Thursday.
The latest U.S. patrol in the disputed South China Sea occurred in advance of President Barack Obama's visit to the region next week to attend Asia-Pacific summits where he is expected the reassert Washington's commitment to freedom of navigation and overflight in the area.
China claims most of the South China Sea, through which more than $5 trillion in global trade passes every year, and the United States has said it will continue conducting patrols to assure unimpeded passage. Vietnam, Malaysia, Brunei, the Philippines and Taiwan have rival claims in the region.
In the latest mission, which occurred overnight on Nov. 8-9, the bombers flew "in the area" of the Spratly Islands but did not come within the 12-nautical-mile zones that China claims as territory around islands it has built in the chain, said Commander Bill Urban, a Pentagon spokesman.
"The B-52s were on a routine mission in the SCS (South China Sea)," taking off from and returning to Guam, Urban said.
Chinese ground controllers contacted the bombers but the aircraft continued their mission unabated, Urban said.
"We conduct B-52 flights in international air space in that part of the world all the time," Pentagon spokesman Peter Cook told a news briefing earlier on Thursday.
Last month, a U.S. warship challenged territorial limits around one of China's man-made islands in the Spratly archipelago with a so-called freedom-of-navigation patrol, the most significant U.S. challenge yet to territorial limits China claims around its new islands. China reacted angrily to the patrol.
White House spokesman Josh Earnest said he did not know whether the South China Sea would be on the formal agenda at any of the three Asia summits that Obama will attend but added that it would be “on the minds and lips” of world leaders who gather there.
Obama's first stop will be Manila for the Asia-Pacific Economic Cooperation forum summit, where Chinese President Xi Jinping will also be present. The U.S. president will then go to Kuala Lumpur for ASEAN and East Asia summits.
"We are quite concerned about protecting freedom of navigation, the free flow of commerce in the South China Sea," Earnest told reporters. "And we're going to continue to encourage all parties, big and small, to resolve their differences diplomatically and to not try to use their comparative size and strength to intimidate their neighbors."
In an apparent show of U.S. resolve, Obama will take part in what the White House described as “an event that showcases U.S. maritime security assistance to the Philippines". U.S. officials did not elaborate.
But in September, Navy Admiral Harry Harris, head of the U.S. Pacific Command, visited the National Coast Watch Center, a facility at the Philippines coast guard headquarters that Washington has helped Manila build to improve its ability to monitor developments in the South China Sea.
(Additional reporting by Matt Spetalnick; editing by Doina Chiacu, Christian Plumb and Ken Wills)