Special to WorldTribune.com

China is bolstering its anti-submarine warfare capability by building a third airstrip on man-made islands and extending its reach in the South China Sea, according to Chinese and Western experts.

A third airstrip in the Spratly archipelago would allow Beijing to extend the reach to more than 1,400 kilometers (870 miles) from the Chinese mainland of Y-9 surveillance planes and Ka-28 helicopters that are being re-equipped to track submarines.

Satellite photographs show construction is almost finished on a 3,000-meter-long (10,000-foot) airstrip on Fiery Cross Reef. Recent images showed Subi Reef would have the same length airstrip, Greg Poling, director of the Asia Maritime Transparency Initiative at the Center for Strategic and International Studies think tank in Washington, said. Poling, citing images taken last week, said China also appeared to be doing preparatory work for an airstrip on Mischief Reef.

Together, the three islands form a rough triangle in the heart of the Spratlys, where the Philippines, Vietnam, Malaysia, Brunei and Taiwan all have competing claims.

A Pentagon report in May said that China had lacked a strong anti-submarine warfare capability off its coastline and in deep water.

Zhang Baohui, a mainland security specialist at Hong Kong’s Lingnan University, said improved anti-submarine capabilities could also help Beijing protect the movements of its Jin-class submarines, which are capable of carrying nuclear-armed ballistic missiles.

“That would provide greater security for China’s nuclear submarines to survive … and if necessary to execute their orders in wartime,” Zhang told Reuters. “They would be safer than in open oceans where China cannot provide adequate support.”

The Obama administration has bee critical of China’s buildup of the artificial islands and the topic is expected be high on the agenda when Chinese President Xi Jinping meets with U.S. President Barack Obama in Washington next week.

China has repeatedly stressed it has “indisputable sovereignty” over the entire Spratlys, saying the islands would be used for civilian and undefined military purposes.

U.S. Defense Secretary Ashton Carter on Sept. 16 said the United States would “fly, sail, and operate wherever international law allows. Turning an underwater rock into an airfield simply does not afford the rights of sovereignty or permit restrictions on international air or maritime transit,” Carter told a U.S. Air Force conference.

  China extends reach in S. China Sea with third man-made island airstrip, Fiery Cross Reef, Mischief Reef, Subi Reef, WorldTribune.com, Xi Jinping