A Chinese fishery administration ship leaves the Xingang Port of Haikou in Hainan Province, on March 26, 2013, to conduct patrol missions in waters off the Paracel Islands and Scarborough Shoal in the South China Sea. (Guo Cheng/Xinhua via AP)

After a week of acrimonious accusations between China and Vietnam, the Chinese military has admitted that one of its ships fired at a Vietnamese fishing boat, although it insisted that only flares were shot and that Vietnam’s claims of fire damage to the fishing boat were a “sheer fabrication.”

The altercation and angry rhetoric are just the latest in a string of maritime clashes over territory between China and many of its neighbors. But at their worst, such run-ins have consisted of boats ramming each other, the use of water cannons and the arrests of fishermen, and they have rarely escalated to the firing of shots. The clash and the prolonged trading of barbs for days afterward point to a worsening rift between the two communist countries.

Vietnamese leaders say the fishing boat was near the disputed Paracel Islands on March 20 when the Chinese vessel began to chase it. The crew of the Vietnamese boat told local news media that the Chinese ship fired at their boat four to five times and set its cabin ablaze.

Vietnamese officials called the incident serious and life-threatening. Vietnam lodged a complaint with the Chinese Embassy in Hanoi and insisted that China pay reparations to the fishermen.

After a week of silence, China’s Defense Ministry posted a statement late Tuesday on its Web site justifying the Chinese actions. The ministry said that the Vietnamese boats “illegally” entered Chinese waters and that a Chinese patrol vessel tried to warn the fishing boat with whistles, shouts and hand-flag signals. When those failed, the Chinese naval crew fired two red flares, both of which burned out in the air, the ministry said.

In its statement, the Chinese military also portrayed itself as a model of restraint. It said that since last year, at least 303 Vietnamese fishing boats have entered the disputed waters but that China has refrained from capturing such boats “out of concerns of maintaining military relations.”

Vietnam is just one of many countries now feuding with China. The tensions have escalated as China’s military has grown stronger and Chinese leaders have asserted their claims more boldly.

In the South China Sea, where the clash with Vietnam took place, China is vying with six other sovereign states. Of them all, China has laid claim to the largest portion — virtually the entire sea.

The region is believed to hold much untapped oil and natural gas — energy resources that China is desperate to acquire to continue fueling its economic growth. The clashes resulting from its stance have been especially fierce with the Philippines, which claims islands off its coasts, notably the Spratlys and Scarborough Shoal.

At the same time, Beijing’s dispute with Tokyo over maritime territories to China’s east has also heated up. In the latest skirmish, Japanese officials said a Chinese naval vessel locked a weapons-guiding radar onto a Japanese ship in the disputed area. Beijing denied the accusation.

The United States has moved carefully to support longtime allies such as Japan and the Philippines, as well as regional partners such as Vietnam, without offending China.

Even as the clashes have increased neighbors’ perceptions of China as a threat, Beijing has signaled recently that it will maintain its more aggressive stance.

“For a long time, China was restrained and conciliatory in the territory disputes with neighbor countries. Some countries took this to mean China was weak and could be bullied anytime,” Maj. Gen. Luo Yuan, executive director of the China Military Science Society, said in a telephone interview. “China tries to use peaceful measures to resolve the disputes. But if all the diplomatic measures and the administrative measures don’t work, China will take military measures.”

Zhang Jie contributed to this report.