HO CHI MINH CITY, Vietnam — The Olympic torch was paraded through the streets of Vietnam's largest city Tuesday on the final leg of an international tour that has been dogged by protests against China.

Hundreds of flag-waving supporters cheered as the relay began in downtown Ho Chi Min City. Security along the route was tight and there were no immediate signs of any protesters.

Earlier police detained several people in the capital, Hanoi, for an anti-China banner and shouting "Boycott the Beijing Olympics" in a market, two witnesses said. They spoke on condition of anonymity, because they were afraid of getting into trouble with authorities in this communist country.

Police refused to comment on the incident.

Vietnam has assured its communist ally and giant northern neighbour it will not allow demonstrators to disrupt the parade, though students have threatened to protest China's claim to the disputed Spratly Islands.

The torch arrived in Vietnam late Monday from North Korea, where tens of thousands of citizens were mobilized to celebrate the relay in Pyongyang in the flame's first visit to the authoritarian nation.

China and Vietnam fought a border war in 1979, but relations between the two communist countries have improved greatly in recent years.

At many of its 18 stops, the relay has been beset by protests against China's human rights record and a recent crackdown in Tibet following anti-government riots. Large groups of patriotic, flag-waving Chinese also have turned out, in some cases clashing with protesters.

From Vietnam, the flame will travel to the Chinese territories of Hong Kong and Macau before heading to the mainland, including the restive Tibet region and to the top of Mount Everest.

On Tuesday, Students for Free Tibet spokeswoman Lhadon Tethong said that two fellow activists were detained and questioned at Hong Kong's airport and that Hong Kong officials were trying to put one of them on a return flight to New York.

Hong Kong Immigration Department spokeswoman Ho Tse Bing-yee declined comment.