Myanmar's junta on Wednesday detained three pro-democracy activists hours ahead of a ceremony marking the 18th anniversary of the formation of Aung San Suu Kyi's opposition party, a spokesman and a family member said.
Min Ko Naing, Ko Ko Gyi and another activist were taken by Myanmar authorities without being given any reason, said Myint Thein, a spokesman for the National League for Democracy (NLD) party.
A relative of Min Ko Naing confirmed their detention but could not identify the third activist. Myanmar authorities declined to comment.
The activists were scheduled to attend a ceremony commemorating the 18th anniversary of detained democracy icon Aung San Suu Kyi's NLD party at its headquarters in Yangon.
Min Ko Naing and Ko Ko Gyi, both in their 40s, led a bloody student uprising in August 1988 to demand an end to military dictatorship. The military has ruled Myanmar since 1962.
Troops opened fire on mass student protests, and thousands of people may have been killed, according to estimates.
A month after the bloody uprising, Aung San Suu Kyi helped found the NLD, which won 1990 elections in a landslide. But the military never recognized the results.
While Min Ko Naing and Ko Ko Gyi are not NLD members, both have already spent more than a decade in prison for their protests against the military government.
Aung San Suu Kyi, a 61-year-old Nobel peace laureate, has spent 10 of the last 17 years under house arrest, locked in her home in Yangon.
Myanmar in May extended her detention for another year, defying an international outcry demanding her freedom.