Pro-democracy activists rallied in the Burmese capital, Rangoon, to mark the 17th anniversary of Aung San Suu Kyi's party's victory in national polls.
NLD activists called for leader Aung San Suu Kyi to be released
Some 200 members of her National League for Democracy (NLD) gathered to shout slogans and call for Ms Suu Kyi's release from house arrest.
The rally came on the day her latest detention period was due to expire.
But on Friday Burma's military junta extended it by another year, drawing swift international condemnation.
Ms Suu Kyi, 61, has spent 11 of the last 18 years in detention.
In 1990 her NLD won national elections, but these were annulled by the army and she was never allowed to take power. Her latest period of house arrest began in May 2003.
In a statement, the NLD called on Burma's military rulers to enter into dialogue and reopen their party offices.
"Release immediately and unconditionally all political prisoners of conscience including members of parliament who are imprisoned for their beliefs," the statement said.
Around 50 plainclothes policemen watched the rally and took photographs of participants, witnesses told the French news agency AFP.
The activists planned to hold a ceremony to mark the election victory before going to a temple to pray for Ms Suu Kyi's release, one man told the agency.
The US, EU and UN have all condemned the order to extend her detention.
But it was widely expected, as under Burmese law Ms Suu Kyi's house arrest must be renewed every 12 months.