Burmese activists say a court in that military-ruled country has sentenced three ethnic minority activists and two Buddhist monks to prison, in the latest crackdown on pro-democracy supporters.

Employees of the notorious Insein prison make their way out through the main entrance of the facility in Burma's biggest city, Rangoon, 23 Sep 2008

An ethnic minority leader, Chin Sian Thang, told VOA Burmese service Tuesday that a court inside Rangoon's Insein Prison sentenced his son, nephew and another student to 33 years in prison.

The three had formed an ethnic minority branch of the prominent dissident group the 88 Generation Students.  They were convicted of inciting public unrest under Burma's emergency act.

The ethnic minority leader who reported their sentencing won a parliamentary seat in the 1990 elections, but he has never served because the military government ignored the election results.

Another pro-democracy activist told VOA two monks also were convicted Tuesday for joining last year's rare pro-democracy demonstrations.

One of the monks, Ashin Gambira, was a prominent leader of the demonstrations. VOA's source says Ashin Gambira was sentenced to 12 years in prison and still faces more charges.

Activists tell VOA the other monk, U Kalatha, received a 35-year sentence.

Burma's courts have sentenced at least 86 other pro-democracy activists to lengthy prison terms in recent weeks.

The United Nations human rights envoy to Burma and other U.N. experts are calling for the activists' retrial.

In a statement Tuesday, U.N. envoy Tomas Ojea Quintana urged Burmese authorities to stop harassing and arresting individuals for peacefully exercising their internationally recognized human rights.

He and other U.N. experts demanded that Burma stop trying activists inside prisons and hold fair and open trials for all of the detainees.  They also called for the release of several defense lawyers who were jailed while defending political detainees.