Human Rights Watch says Burma's military government has doubled the number of political prisoners over the past two years.
The New York-based advocacy group Wednesday said Burma is holding more than 2,200 political prisoners, with 100 people jailed in recent months.
Burma has dismissed criticism of its human rights record and says it is implementing a so-called "roadmap to democracy." The plan includes holding national elections next year for the first time in 20 years.
Human Rights Watch says Burma should immediately and unconditionally release all political prisoners in Burma if the elections are to have any credibility.
The United States is reviewing its policy toward Burma to determine how best to encourage the government to reform. The top U.S. diplomat for Southeast Asia, Scot Marciel, said Wednesday that review will be concluded soon.
He said even if the policy changes, the ultimate goal will be for Burma to release political prisoners and have a more inclusive political process.
Burma has been under military rule since 1962. The opposition National League for Democracy won the last elections in 1990, but the military government refused to acknowledge the results.
Opposition leader Aung San Suu Kyi has been in some form of detention for 14 of the past 20 years.
She was convicted last month of violating the terms of her house arrest when she allowed an uninvited American man to rest at her home in Rangoon for two days.
Her lawyer says authorities have refused her request to attend an appeal hearing. A court in Rangoon will hear the appeal on Friday.
Some information for this report was provided by AFP and Reuters.