Relatives of Burmese dissidents say courts in Rangoon have sentenced at least 20 more activists to prison in a sweeping crackdown on dissent.

Family members and an opposition party spokesman, Nyan Win, told VOA Burmese service the activists were sentenced Thursday to between two and 12 years in prison.

Most of the prisoners are youth members of the opposition National League for Democracy party. Others belong to the country's most defiant activist group, the 88 Generation Students.

Some of the activists joined last year's rare pro-democracy protests. Others joined a peaceful march calling for the release of detained democracy leader Aung San Suu Kyi.

The U.S. State Department and United Nations condemned Burma's sentencing of at least 30 other political prisoners this week, including student and labor activists, Buddhist monks and a blogger.

Some were sentenced to 65 years in prison.

The fate of Burma's two most prominent student leaders is still unknown. Min Ko Naing and Ko Ko Gyi of 88 Generation Students have been transferred from Insein prison to the Maoubin prison outside Rangoon and are awaiting their sentencing.

New York-based Human Rights Watch says Burma's military government is using lengthy prison terms to silence dissent ahead of its 2010 elections.

The last time Burma held general elections, in 1990, the opposition party won a major victory. The military government refused to recognize the results and has kept opposition leader Aung San Suu Kyi under house arrest for 13 of the past 19 years.

At least 2,000 other political prisoners are jailed in Burma.