Updated

The Pentagon protested Friday against Tuesday's "very close, very dangerous" intercept by a Chinese fighter jet of a U.S. Navy P-8A Poseidon aircraft over the South China Sea off the Chinese island of Hainan.

"We expressed our concerns through diplomatic channels," Rear Adm. John Kirby, the Pentagon press secretary, said at a briefing. The incident occurred Aug. 19 over international waters about 135 miles east of Hainan, Kirby said.

Kirby did not identify the type of Chinese fighter, which he said made several dangerous passes past the Poseidon, coming within 30 feet at one point. However, photos later released by the Pentagon showed what appeared to be a Chinese J-11B fighter aircraft.

The Chinese jet also did a barrel roll over the Poseidon and passed in front of the nose of the U.S. aircraft to show its belly and the missile pods on the underside of its wings, Kirby said.

Deputy National Security Advisor Ben Rhodes later called the Chinese action a "deeply concerning provocation" and said U.S. concerns had been conveyed to Beijing.

The incident was the latest aggressive action by China to assert its authority in the South China and East China Seas, where it has territorial disputes with Japan, Vietnam, the Philippines, Taiwan and South Korea.

U.S. aircraft routinely patrol off China's coast and the U.S. has repeatedly asserted its right to conduct the flights over international waters.

The P8-Poseidon, a modified version of the Boeing 737, was designed to replace the Navy's P-3 Orion patrol aircraft. The Poseidons are configured to conduct anti-submarine and anti-surface warfare with an array of missiles and depth charges, and they also can carry out electronic signals intelligence missions.

Poseidons were recently deployed over the Indian Ocean to aid in the search for missing Malaysian Airlines Flight 370.

The incident near Hainan recalled the April 2001 collision near the island between a Navy EP-3 Orion and a Chinese J-8 fighter. The pilot of the Chinese fighter was killed but the badly-damaged Orion and its crew of 24 landed safely on Hainan. The crew was questioned for a week before being released.

-- Richard Sisk can be reached at richard.sisk@monster.com