HANOI - Vietnam announced a live ammunition drill in the South China Sea.

Vietnam said Friday its Navy would carry out two exercises totaling nine hours Monday in an area off the country's central Quang Nam province. The announcement posted on the state-owned Northern Maritime Safety Corp's website warned boats and ships to stay out of the area. It was the first time Vietnam has issued such an alert about conducting maritime drills.

On Thursday, China accused Vietnam of illegally entering its waters and endangering its fishermen's lives. Hours earlier, Vietnam had slammed China for interfering with its seismic survey off the country's central coast, saying the Chinese fishing boat supported by two patrol vessels had damaged an exploration cable on a survey boat hired by state-owned PetroVietnam.

Chinese foreign ministry spokesman Hong Lei said the Chinese fishing boat crew had merely been protecting itself after being dragged backward for over an hour by a Vietnamese vessel - one, he said, that was illegally working at the scene.

In Washington, State Department spokesman Mark Toner said the recent incidents had raised tensions and concerns about maritime security.

"The US, like many other nations, has interests in the South China Sea. What there needs to be is a collaborative diplomatic process, a peaceful process, to resolve various territorial disputes. Shows of force, other gestures like that, just I think raise tensions," he told a news conference.