Two Chinese Sukhoi Su-30 Jets performed an "unprofessional" section of an American aircraft

Supernaij

Two Chinese Sukhoi Su-30 Jets performed an "unprofessional" section of an American aircraft, the US Army said.

The US-135 aircraft were on a mission to detect radiation in the international airspace across the East China Sea.

One of the Chinese rays came as close as 150m (45m) to the American plane, according to US officials cited by CNN.

China's suspicion of US activities near the resource-rich international waters of the coast has repeatedly led to tension between the two countries.

"The issue is being addressed with China through appropriate diplomatic and military channels," said air spokeswoman Lt Col Lori Hodge.

China claims sovereignty over almost all the contested areas in the South and East China, although several other countries in the region have competitive demands.

China has supported its extensive claims with island and fleet patrols.

Why is the South China Sea controversial?

South China Sea- Island, Rock or Reef?

The suspension was considered unprofessional "because of the maneuvers by the Chinese pilot, as well as the speed and proximity of both aircraft," Lt Col Hodge said. A military investigation is under way.

The US sniffer plane was previously used to detect evidence of possible nuclear tests by North Korea.

'Routine operations'

On the whole, China and Southeast Asian countries have provided a framework for a long-awaited code of conduct for the disputed South China Sea, China's Foreign Ministry, without giving details about the content.

It will now be presented to the foreign ministers of the countries in August.

Over the years, the USA, China and several of the Southeast Asian countries have verbally collided with activities in the South China Sea.

In February, an American airline company began to describe Washington as "routine operations" in the South China Sea, with a fleet of supporting warships.

The deployment came despite Chinese warnings against the pursuit of Beijing's sovereignty in the region.

In May 2016 two Chinese fighters performed a similar section of an American military plane over the South China Sea.