"What we have encouraged is constructive military-to-military ties with China and this type of action ... clearly violates the spirit of that engagement, and we have made our concerns known directly to Beijing," he said.
Rear Admiral John Kirby, the US defence press secretary, said that a Chinese fighter pilot performed acrobatic maneuvers around the Navy patrol plane, and flew a few metres from the US jet. Kirby said the US lodged a formal diplomatic protest with Beijing over the incident, which took place on Tuesday about 215km east of Hainan Island, site of a sensitive Chinese submarine base. Kirby said the Chinese fighter jet made several passes at the P-8 Poseidon anti-submarine and reconnaissance plane, crossing over and under it. At one point, the jet flew wingtip-to-wingtip about 9 metres) from the Poseidon, then performed a barrel roll over the top of it, he said.
"The Chinese jet also passed the nose of the P-8 at 90 degrees with its belly toward the P-8 Poseidon, we believe to make a point of showing its weapons load," Kirby said.
The US Navy's P-8 Poseidon aircraft are designed for long-range missions including intelligence collection and reconnaissance.