About 500 activists and opponents of Burma's military-ruled government have held a rare ceremony inside the country to mark the deaths of hundreds of people killed in a nationwide pro-democracy uprising nearly two decades ago.

Members of the National League for Democracy, diplomats and others attended the ceremony Wednesday at a Buddhist monastery in Rangoon, as security officers watched.

In other parts of Southeast Asia, activists rallied to mark the uprising on August 8, 1988.

In Washington, State Department spokesman Sean McCormack said Burma's military rulers must engage in dialogue with leaders of the democracy movement and cease what he said are "human rights abuses against civilians." He renewed a call for the government to release all political prisoners, including democracy leader Aung San Suu Kyi.

Burma held elections two years after the 1988 uprising. The opposition NLD won a landslide victory, but military leaders refused to recognize the results of the race.

The party's secretary-general, Nobel Peace Prize laureate Aung San Suu Kyi, has spent most of the past 18 years under house arrest.