Myanmar's army-backed regime is expected to free more political prisoners on Monday, in the latest sign of change in the repressive state, as democracy icon Aung San Suu Kyi marks one year of freedom. The planned amnesty comes just days before Myanmar's military-dominated government is due to attend a meeting of the Association of Southeast Asian Nations (ASEAN) regional bloc in the Indonesian island of Bali. A mass prisoner amnesty was held last month but did not include most key dissidents, disappointing observers and the opposition. The release of all of the country's political detainees, who include democracy campaigners, journalists and lawyers, is one of the major demands of Western nations which have imposed sanctions on Myanmar. An official Myanmar source, who did not wish to be named, told AFP on Monday that the amnesty would go ahead. "The release will happen. The senior officials are still checking the list carefully for the release and for moving prisoners of conscience to prisons where they can have easy access to their families," the source said. "We are waiting for the final decision of senior officials." Myanmar, which has shown tentative signs of reform in recent months, appears keen to end its international isolation and is seeking to take the ASEAN chair in 2014. Since taking power in March, President Thein Sein, a former general, has surprised critics by holding direct talks with opposition leader Suu Kyi and defying key ally China by freezing work on an unpopular mega-dam project. The new regime, which replaced a long-ruling military junta after a controversial election, pardoned more than 6,300 prisoners -- including about 200 political detainees -- in a much-anticipated amnesty in October. Among those released were members of Suu Kyi's National League for Democracy (NLD) party and celebrated comedian and vocal government critic Zarganar, who uses only one name. But many leading dissidents, including key figures involved in a failed student-led uprising in 1988, were kept behind bars. Monday's prisoner release is likely to coincide with a press conference by Suu Kyi marking the first anniversary of her release after years of house arrest, just days after the country's elections in 2010. Her NLD party was de-listed last year for boycotting the first polls in 20 years, but its members will discuss this Friday whether to re-register following changes to political party laws, paving the way for Suu Kyi's comeback. The exact number of political prisoners currently imprisoned in Myanmar is unclear. Before last month's amnesty, rights groups and observers believed the country had roughly 2,000 political detainees but NLD spokesman Nyan Win said the real number was around 500. US Secretary of State Hillary Clinton on Thursday said the United States was ready to become a "partner" of Myanmar if the government pursued "genuine and lasting reform".