YANGON, Myanmar — Myanmar’s longest-serving political prisoner, journalist Win Tin, was freed Tuesday after 19 years behind bars and vowed to continue his struggle to achieve democracy in the military-ruled country.
    Win Tin’s release came as part of an amnesty granted Tuesday to 9,002 prisoners around the country. It was not immediately clear how many of those released were political prisoners. Amnesty International said last month there were 2,050 political prisoners in Myanmar.
    The amnesty came just days ahead of the one-year anniversary of the junta’s deadly crackdown on anti-government protests that were led by Buddhist monks. The U.N. estimated at least 31 people were killed when the army fired on peaceful protesters in the Sept. 26-27, 2007 crackdown, sparking global outrage.
    The 78-year-old Win Tin said he would continue to wear his light blue prison uniform as a show of protest against the junta, which has ruled Myanmar for 46 years.
    ‘‘I have to continue with my unfinished task of trying to achieve democracy in Myanmar,’’ Win Tin told reporters at a friend’s home in Yangon after his release from the notorious Insein Prison. He appeared alert and healthy despite recent reports that he is ill.
    Asked how it felt to be out of prison, Win Tin replied, ‘‘I will be happy only when all political prisoners, including Aung San Suu Kyi, are released.’’
    A longtime journalist and poet, Win Tin became active in opposition politics and helped found Aung San Suu Kyi’s National League for Democracy opposition party in 1988. He was a close aide to Suu Kyi, a Nobel Peace Prize winner who is currently under house arrest.
    Win Tin was arrested on July 4, 1989, during a crackdown on opposition politicians. Tried in a military court, he was sentenced to 14 years in prison for allegedly being a member of the banned Communist Party of Myanmar.
    He was most recently sentenced in March 1996 to an additional seven years’ imprisonment for writing to the United Nations about prison conditions and for writing and circulating anti-government pamphlets in prison, which authorities characterized as ‘‘secretly publishing propaganda to incite riots in jail,’’ the statement from London-based Amnesty said.
    The United Nations and international rights groups had repeatedly called for the release of Win Tin and referred to him as the longest-serving political prisoner in Myanmar.
    While incarcerated, Win Tin had two heart attacks, a hernia operation and suffered from high blood pressure, diabetes and spinal inflammation, according to international media groups.
    State-controlled media announced the prisoner amnesty Tuesday, saying that freedom was granted to prisoners around the country who exhibited good ‘‘moral behavior.’’
    ‘‘The government is trying to transform these convicted prisoners into citizens who can contribute to the building of a new nation,’’ the Myanma Ahlin newspaper said, adding they were released ‘‘so they could participate in the fair elections to be held in 2010.’’
    The elections are part of the junta’s long announced ‘‘roadmap to democracy,’’ which will give voters the first chance to cast ballots since 1990.
    Critics say the roadmap is a sham designed to cement the military’s power.
    In 1990, Suu Kyi’s opposition party won a landslide victory that the junta refused to acknowledge. Instead, the generals stepped up arrests and repression of dissidents. Suu Kyi has spent more than 12 of the past 19 years in detention, mostly under house arrest.
    The government often grants prisoner amnesties to mark important national days, but usually most of those released are petty criminals.