The Chinese officials warned a US military aircraft flying near South Korea on Sunday during routine operations in international airspace.

CNN reported citing a US defense official as saying that the Chinese side told the pilots that they were illegally operating in Chinese airspace and ordered the American plane to leave.

The pilots of the US Air Force B-1B Lancer bomber responded to the Chinese air traffic controllers, saying that they were conducting routine operations in international airspace and did not deviate from their flight path, according to US Pacific Air Forces spokesman Major Phil Ventura.

The bombers had entered a controversial Chinese Air Defense Identification Zone (ADIZ) in the East China Sea, which covers a disputed island chain and overlaps with airspace claimed by Japan and South Korea.

The ADIZ declaration required airlines flying over the designated waters to first notify the Chinese authorities before transiting. The US and Japan do not recognize China's claim on the area.

"Pacific Air Forces ... did not recognize the Chinese Air Defense Identification Zone (ADIZ) when it was announced in November of 2013, and does not recognize it today," Ventura told CNN.

China established the zone despite objections from Tokyo and Washington. A US report published last year suggested that it was not being fully enforced.

According to the US Air Force, the Guam-based B-1 bomber was conducting a series of training missions with the Japanese and South Korean military aircraft.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)