BEIJING — A Chinese fishing vessel rammed and sank a Vietnamese fishing boat near the Chinese deepwater oil rig that was placed in disputed waters off the coast of Vietnam, according to the state-run Vietnamese television network, VTV1.

Vietnamese fishing boats operating in the area rescued 10 fishermen who were on the boat that was hit, about 17 nautical miles southwest of the rig, VTV1 said.

The collision on Monday afternoon was likely to escalate the already high tensions between China and Vietnam over the oil rig, which arrived off the Paracel Islands in the South China Sea on May 1.

Vietnam claims the waters around the oil rig are within its 200-nautical-mile exclusive economic zone, and has threatened to take China to an international arbitration court.

Map | Territorial Disputes in the Waters Near ChinaChina has recently increased its pursuit of territorial claims in nearby seas, leading to tense exchanges with neighboring countries. A map of some of the most notable disputes.

“Suddenly Chinese fishing boat #11209 crashed into Vietnamese fishing boat DNa 90152 with 10 fishermen on board,” the VTV1 report said. A deputy colonel in the Vietnamese Coast Guard, Ngo Ngoc Thu, said the Chinese vessel had a steel hull.

Chinese and Vietnamese boats have rammed each other in the area around the oil rig, and the Chinese have acknowledged they used water cannons to keep Vietnamese boats away from it.

As many as 80 Chinese vessels, including some from the Coast Guard, patrol the rig and a wide perimeter, according to Vietnamese accounts.

The episode came after anti-Chinese riots in Vietnam at Chinese-run factories that resulted in the deaths of four Chinese workers and injuries to more than 100. China evacuated several thousand workers from Vietnam last week, and warned Vietnam, a usually friendly country, to stop the protests over the deployment of the oil rig.

In one protest, a 67-year-old Vietnamese woman died when she set herself on fire in the center of Ho Chi Minh City last week, an echo of the self-immolations by Buddhist monks during the Vietnam War.

The Chinese state-run news agency, Xinhua, reported Tuesday that the oil rig, operated by the energy giant CNOOC, had completed its first phase of work and would remain in the area until mid-August. The United States has urged both China and Vietnam to use restraint. The sinking of the fishing boat was just the sort of thing that the United States was concerned about, said Dennis J. Blasko, a former military attaché at the American Embassy in Beijing.

“The Vietnamese are going to say the Chinese rammed, and the Chinese are going to say the Vietnamese rammed and no one will know the real story,” Mr. Blasko said.

 The Chinese government has provided navigation systems, called Beidou, a rival to GPS, to fishing boats since last year, according to Xinhua, adding that about 80 percent of China’s fishing vessels carry the systems. 

Bree Feng contributed reporting from Beijing, Chau Doan from Hanoi, Vietnam, and Chris Buckley from Hong Kong.