HANOI, Vietnam -- Vietnam's prime minister, Nguyen Tan Dung, accused China on Sunday of "dangerous and serious violations" in a territorial dispute that has raised anger toward China here to the highest levels in years.
Mr. Dung's comments, which were carried in Vietnamese state media, were addressed to leaders of Southeast Asian countries attending a summit meeting in Myanmar. It was his strongest statement since China towed a huge oil rig into disputed waters off the coast of Vietnam this month.
"This extremely dangerous action has been directly endangering peace, stability, security and marine safety," Mr. Dung was quoted as saying, adding that Vietnam had acted with "utmost restraint."
Mr. Dung's comments were uncharacteristically spirited for the typically anodyne meetings of the 10-country Association of Southeast Asian Nations, but they failed to produce a collective public response. The leaders, who work by consensus, did not mention the dispute in their final statement Sunday.
Their refusal to weigh in appeared to be a victory for China and underlines how there does not yet appear to be a willingness or ability to address the territorial disputes in the South China Sea collectively. At least five nations claim islands in the sea, a major shipping lane and potential flash point as China becomes more assertive and hungry for resources.
Murray Hiebert, an expert on Southeast Asia at the Center for Strategic and International Studies in Washington, said Vietnam and the Philippines, another vocal critic about Chinese maritime claims in the South China Sea, "clearly wanted something a lot stronger" out of the meeting.
ASEAN has been unable in recent years to reach a common position on the South China Sea even as China's claims have reached more than 1,000 miles southward from the Chinese mainland. A summit meeting in Cambodia two years ago failed to produce a final statement because leaders quarreled over the issue.
China is the region's largest trade partner, and countries like Cambodia and Laos are large recipients of its aid.
"Within ASEAN, you have countries that really don't want to rock the boat," Mr. Hiebert said. "They are playing it pretty much down the middle."
Foreign ministers at the meeting in Myanmar issued an oblique statement Saturday citing "serious concerns over the ongoing developments in the South China Sea," but did not mention China by name.
Several hundred protesters demonstrated peacefully outside the Chinese Embassy in Hanoi on Sunday, and Vietnam's authoritarian government took the rare step of permitting journalists from the state-controlled news media to cover the protest. Signs displayed slogans like "Denounce the Chinese Invasion."
"We don't have a problem with Chinese people or their culture, but we resent their government conspiring against us," Nguyen Xuan Pham, a literary critic, said as the protest swelled in a public park across from the embassy and a military museum.
China towed the oil rig this month to waters near the Paracel Islands, which China controls and Vietnam claims.
China's state-controlled Xinhua news agency said Sunday that the oil rig was "completely within" China's territorial waters. The rig is 140 miles off the coast of Vietnam.
The maritime standoff with China, which has controlled the islands since 1974, has been widely discussed both in Vietnam's state-controlled news media and on Facebook, which is very popular among the country's urban middle class.
China is one of Vietnam's major trading partners, and both countries have nominally socialist one-party governments. But Vietnamese officials sometimes appeal to anti-China sentiments here that are never far from the surface and rooted in a history of conflict between the countries.
The Vietnamese government is balancing a desire to appear strong against China with the fear that anti-China sentiment could unite disgruntled citizens who have festering grievances over land grabs, religious persecution and other hot-button social issues.
Protesters Sunday presumed to be plainclothes agents occasionally shoved and yelled at other protesters, but most uniformed security personnel sat nearby and did not interfere.