Hanoi - At least six people protesting the Beijing Olympics were detained Tuesday in Hanoi ahead of the Olympic torch relay through Ho Chi Minh City later in the day.

Two men hoisted banners with the words "Beijing 2008" and a design depicting the Olympic rings as handcuffs at Hanoi's Dong Xuan market before being hustled away by dozens of uniformed and plainclothes police officers.

A desk officer at the local police station said a police rapid reaction unit had brought in six detainees Tuesday morning but would not release their names.

Larger Hanoi demonstrations called for on the blogs of local democracy activists seemed not to have materialized. Police were present in unusual numbers at the Chinese embassy and at Dong Xuan market before the demonstration had begun.

Exile Vietnamese pro-democracy groups said a much larger group of demonstrators had been detained by police on their way to a protest at Hoan Kiem lake, but these arrests could not be verified.

Vietnamese democracy bloggers called for more protests later Tuesday in Ho Chi Minh City.

The protests in Vietnam are oriented toward Vietnamese resentment of China's claims to the Spratly and Paracel islands, two possibly oil-rich archipelagos in the South China Sea over which Vietnam also claims sovereignty.