The heated verbal clash between the two communist neighbors comes amid a similar spat between China and Philippines earlier in the week over another disputed area of the South China Sea, where several countries are eyeing potentially rich oil and gas reserves.

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.

It came a day after China and Vietnam traded diplomatic punches, with each demanding that the other stay out of waters they claim. The two countries have a long history of maritime scraps in disputed parts of the South China Sea near the Spratly and Paracel islands, but the recent row has sparked an unusually hostile response from Hanoi.

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.

Vietnam said it was the second time China had hindered the operation of an oil and gas exploration boat in two weeks, adding that its actions were "completely premeditated" and accusing it of flaring regional tensions in the South China Sea.

Hanoi says both incidents occurred well within the 200 nautical miles guaranteed to Vietnam as an exclusive economic zone by international law. The incident is stoking nationalism, with thousands of Vietnamese marching in Hanoi and Ho Chi Minh City last weekend in rare demonstrations demanding that China stop invading Vietnam’s territory.

Chinese foreign ministry spokesman Hong Lei said the Chinese fishing boat crew had instead been in waters around the Spratly Islands, which are claimed by China and Vietnam and some other Asian nations. He said the crew had merely been protecting itself after being dragged backward for over an hour by a Vietnamese oil and gas exploration vessel — one, he said, that was "illegally working at the scene."

On Thursday, China also denied an allegation by Filipino officials that it had intruded six times since February into areas around the Spratlys claimed by the Philippines.

Maritime disputes generally pit China against its neighbors and have pulled in the United States, which has said it considers some of China’s sea claims to be an infringement of international waters and a possible damper on international trade.