Demonstrators marched in Vietnam's capital Monday to mark the 28th anniversary of a bloody naval battle with China and to denounce Beijing's growing assertiveness in the hotly contested waters of the South China Sea.

About 150 people wearing headbands and carrying large banners circled the busy streets around Hanoi's Hoan Kiem lake chanting "down with invasive China." They laid wreaths for 64 Vietnamese sailors who died in a 1988 clash with Chinese forces in the Spratly Islands.

The protest was small, but significant given Vietnam's history of preventing or breaking up demonstrations. While anti-China sentiment is strong among the public, it is a sensitive issue for the ruling Communist Party.