A People’s Liberation Army Navy crewman looks through binoculars aboard the Liaoning, China’s first aircraft carrier, on Friday. The Liaoning docked at a military port in Sanya, South China’s Hainan Province on Friday. Photo: Xinhua

 
 
The US Department of Defense said that the close encounter between the USS Cowpens and the Liaoning in the South China Sea earlier this month was not "unusual" in a statement released on Monday.

Close military activities of navy from different countries are normal, so it is important for different parties to follow the international maritime rules and maintain the highest security and professional levels, said the statement sent to Phoenix TV via email on Monday, ifeng.com reported.

Also on Monday, the US State Department deputy spokesperson Marie Harf said that the US government has attached great importance to this incident.

"The US regularly conducts military operations in international waters and airspace," she said, adding the US has raised it at a high level with the Chinese Government.

A Chinese source who was familiar with this confrontation told the Global Times that the USS Cowpens was detected by the Liaoning formation when trespassing in a no-sail zone in the South China Sea.

The commander of USS Cowpens soon contacted with the Liaoning formation commander Zhang Zheng through radio.

After a short communication between the two commanders, the US guided missile cruiser left the prohibited area.