More than 200 protesters took to Hanoi's streets on Sunday in the second anti-China rally in the Vietnamese capital this month amid heightened territorial tensions over the South China Sea.
Demonstrators said they were stopped by security forces about 100 metres (330 feet) away from the Chinese embassy in the city, but no arrests were made in the latest public expression of discontent over Beijing's perceived aggression in the sea.
The crowd waved banners and chanted "Paracel -- Vietnam! Spratlys -- Vietnam!" during the peaceful rally, in reference to two potentially oil-rich island chains claimed by both Beijing and Hanoi.
Last Sunday, smaller demonstrations were held in both Hanoi and the southern economic metropolis of Ho Chi Minh City as the maritime dispute once again flared following 11 street rallies on the issue last year.
Protest is rare in the authoritarian country. The first rallies last year were allowed to go ahead without interference, but authorities clamped down on later gatherings, briefly detaining dozens of people after talks between Hanoi and Beijing.
Relations between Beijing and Hanoi have soured recently, with Vietnam attracting China's ire last month after it adopted a law that places the Spratlys under Hanoi's sovereignty.
For its part China in June said it had elevated the administrative status of what it calls the Nansha (Spratly) and Xisha (Paracel) islands from a county to a prefectural-level district.
China's state-backed China National Offshore Oil Corp. also said it was seeking bids for exploration of oil blocks in disputed waters -- a move slammed by Vietnam.
Beijing says it has sovereign rights to the whole South China Sea, believed to sit atop vast oil and gas deposits. The sea is also claimed in whole or part by Taiwan, Vietnam, Brunei, Malaysia, and the Philippines.