Taiwanese defense spokesman Chen Chung-chi told NBC News that one TU-154 surveillance aircraft, one Y-8 surveillance plane and two Su-30 fighters also participated in the mission.

Four of the aircraft flew an anti-clockwise loop round Taiwan, an island a little larger than the state of Maryland that China sees as a breakaway province, before meeting up with the other two planes to the north of the country, Chen said. He did not specify which planes made the complete lap.

None of the planes entered Taiwan’s airspace nor its air defense identification zone, the spokesman added.

He said it was the first time Chinese aircraft have encircled the island on what he described as long-distance surveillance mission.