Vietnam was set to conduct a live-fire naval drill on Monday, a move seen as a military show of force to defy Beijing. This comes after warnings for Hanoi to stop violating China's sovereignty over the South China Sea.

The drill comes a week after Chinese Defense Minister Liang Guanglie met his Vietnamese counterpart at the Shangri-La Dialogue in Singapore, where the two sides stressed the importance of developing the bilateral relationship in a spirit of cooperation.

Calling the drill "a routine annual training activity," the Vietnamese government said the war game would last for nine hours around the Hon Ong Island, about 40 kilometers off its central coast.

The island is about 250 kilometers away from the Xisha Islands and 1,000 kilometers away from the Nansha Islands. China declares indisputable sovereignty over these two archipelagos and their adjacent waters, which belong to the South China Sea. Vietnam contests this authority.

On Thursday morning, Chinese fishing boats were chased away by armed Vietnamese ships while near the Nansha Islands, the Xinhua News Agency reported.

Amid the turmoil, the fishing net of one of the Chinese boats got tangled with the cables of an Vietnamese oil exploring vessel, which was operating illegally in the area.

"The drill is undoubtedly intended as a military show of force toward China," Zhuang Guotu, director of Research School of Southeast Asian Studies at Xiamen University, told the Global Times. "Through the flexing of its muscle, Vietnam wants to demonstrate its resolution to maintain its claims on the Nansha Islands."

Ji Qiufeng, a professor at the School of Foreign Relations at Nanjing University, told the Global Times that Vietnam is testing China's bottom line.

"In response, Beijing needs to make it clear to Vietnam that any challenge to China's sovereignty over the South China Sea cannot succeed," Ji said, noting however that both sides should avoid further escalating tensions.

About 50 people protested outside the Chinese embassy in Hanoi Sunday, waving Vietnamese flags and singing patriotic songs. Around 250 demonstrators in Ho Chi Minh City also held a similar rally, AFP reported.

Carl Thayer, a professor at the Australian Defence Force Academy, told AFP that the anti-China protest may be in the interests of the Vietnamese government "up to a point."

However, the demonstrations could escalate, possibly sparking Chinese protests against Vietnam and aggravating ties between the two sides, Thayer said.

Vietnamese Foreign Ministry spokeswoman Nguyen Phuong Nga said Friday that international involvement to keep the peace in the South China Sea would be welcomed.

Nguyen's words repeated an effort by Hanoi last year to internationalize the South China Sea issue, which won backing from US Secretary of State Hillary Clinton, but met with strong opposition in China.

Also on Friday, US Department of State spokesman Mark Toner said Vietnam's naval drill could raise tensions and called for a collaborative and diplomatic process.

Besides Vietnam, countries such as Brunei, Indonesia, Malaysia and the Philippines have also made claims over waters and territories in the South China Sea, all of which are rejected by Beijing.

In an e-mail statement Saturday, press attache Rebecca Thompson of the US embassy in Manila said, "The US does not take sides in regional territorial disputes."

The brief statement said the US "shares a number of national interests with the international community in the South China Sea" but did not mention the Philippines or the two countries' century-old defense ties, the Philippine Daily Inquirer reported.

"Washington's policy of internationalizing the South China Sea issue remains unchanged, but a conflict in the region also violates its interests. Thompson's message that the US does not pick sides is a strategic warning to certain countries in the region," Su Hao, head of the Strategy and Conflict Management Research Center at China Foreign Affairs University, told the Global Times.

During the celebration of the 113th Filipino Independence Day, Chinese Ambassador to the Philippines Liu Jianchao said China was committed to resolving the South China Sea issue peacefully, and that Sino-Philippines relations remain strong despite certain "tests," the Manila Bulletin reported.

Filipino President Benigno Aquino chose to highlight the cooperation between the two sides, specifically education efforts, rather than dwell on "disagreements," the report said.

Separately, the Philippine military confirmed the holding of a joint naval exercise with the US later this month while noting that it had nothing to do with the tensions in the region.