The United States has lodged a formal protest with Beijing over an air intercept this week in which a Chinese warplane flew close to a US Navy patrol jet and conducted acrobatic manoeuvres around it in international airspace, the Pentagon has said.          

Rear Admiral John Kirby, the Pentagon press secretary, said the intercept took place on Tuesday 135 miles (200km) east of Hainan Island.

He said the Chinese fighter jet flew as close as 20-30 feet (7-10 metres) to the P-8 Poseidon maritime patrol plane and conducted a barrel roll over the plane.