A court sentenced two prominent dissidents Tuesday to 13 years in prison each as the alleged masterminds of the 1989 pro-democracy movement, the heaviest terms in dozens of political trials over the Tiananmen Square protests.

Two other intellectuals also branded as "black hands" in the student-led movement were also sentenced. One was pardoned and freed for his "willingness to repent," and another received a six-year prison term.The four had been charged with the "counterrevolutionary" crime of sedition, a much more serious charge than those leveled against students, workers and others sentenced since the trials began in late December.

The sentences were announced by the Bei-jing Intermediate Court after a full day of hearings. Uniformed police blocked the street around the court building and harassed foreign reporters trying to read the public notice board outside.

Editor Wang Juntao, 33, and economist Chen Ziming, 39, were sentenced to 13 years imprisonment each because they "have shown no willingness to repent," the official Xinhua news agency reported.

Liu Gang, a 29-year-old physicist, was given six years imprisonment. Legal scholar Chen Xiaoping, 30, was "exempted from criminal punishment" because he had surrendered voluntarily and showed "willingness to repent," Xinhua said.

The sentences of Wang and Chen Ziming were the heaviest given so far in three dozen trials of Tiananmen Spring dissidents. Veteran human rights activist Ren Wanding was earlier given seven years.

The trials, closed to foreign observers, have been assailed by Western governments and human rights groups as unfair prosecutions with foregone outcomes. Defendants have been unable to choose their own lawyers or present proper defenses.

Wang and Chen, both veteran dissidents of past democracy campaigns, were accused of stirring up the protests, organizing opposition to the government and interfering with martial law forces called in to suppress the movement.

"Chen and Wang wantonly incited some persons to subvert the people's government and the socialist system, gathered together illegal organizations in Beijing and conducted a series of activities to subvert the people's government," Xinhua said.