Courts in military-ruled Burma sentenced at least 14 members of the opposition party to prison terms Friday, bringing to more than 60 the number of pro-democracy activists jailed this week.

Spokesman for the National League for Democracy (NLD) party Nyan Win said the prisoners sentenced Friday received jail terms between two and 16 years.

On Thursday, at least 20 activists were sentenced to between two and 12 years in prison.

The U.S. State Department and the United Nations expressed concern about the crackdown on political prisoners. They were concerned about some who earlier this week were ordered to spend 65 years behind bars.

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

Many of the jailed dissidents are youth members of the opposition party or the 88 Generation Students -- Burma's most defiant activist group. Others sentenced this week include Buddhist monks and a blogger.

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.

Some information for this report was provided by AFP, AP and Reuters.