Situation in South China Sea is critical to the national security interest of the United States, the White House has said.   

"The (US) president has often talked about how criticallyimportant the security situation is in the South China Sea.It's critical to the national security of the United States,"White House press secretary Josh Earnest told reporters at his daily news conference.   

"It's also critical to the global economy that the free flow of commerce in the South China Sea is something that needs to be maintained," he said, adding that the US is committed to working with other countries in the region to protect it.  

"Because it is a priority you can expect that the president has been briefed on the latest in this situation and will continue to be," Earnest said in response to a question.   

A State department official said the US is "carefully"monitoring China's military developments. 

"We continue to urge China to exhibit greater transparency with respect to its capabilities and to its intentions," state department spokesperson Jeff Rathke said.   

"So in conjunction with that, we encourage China to use its military capabilities in a manner that is conducive to maintaining peace and stability in the Asia Pacific region," he said in response to a question.