The US just flew a bomber over a Chinese-built island in the South China Sea

A US B-52 strategic bomber flew over artificial Chinese-constructed islands in the South China Sea recently and was contacted by Chinese ground controllers but continued its mission undeterred, the Pentagon said on Thursday.

"We conduct B-52 flights in international air space in that part of the world all the time," Pentagon spokesman Peter Cook told a briefing.

"My understanding is there was one B-52 flight, I'm not even sure the date on it, but there was an effort made by Chinese ground controllers to reach out to that aircraft and that aircraft continued its mission ... Nothing changed," said Cook.

Even if this was a routine flight, it comes on the heels of a high-profile US attempt at countering Chinese territorial claims in disputed areas of the South China Sea. On October 27, the US deployed the USS Lassen, a Burke-class guided-missile destroyer, to within a few miles of Chinese-constructed artificial islands in the Subi reef, which are part of the disputed Spatley Island chain.

The purpose of the deployment was to demonstrate that the US did not recognize what would be a legally mandated 12-mile maritime boundary around the islands, which the Chinese built to establish a military and territorial foothold in the area.

The Lassen's deployment did not include US aircraft flying within the 12-mile boundary, and experts believe the operation fell somewhat short of a true freedom of navigation exercise. A bomber flight within the airspace of artificial islands - airspace that China believes is sovereign territory - would be an even more robust message to Beijing that the US doesn't recognize China's extensive claims in the South China Sea.