BERLIN (AP) _ Erich Mielke, once the No. 2 man in East Germany as head of the secret police, went on trial today for the 1931 murders of two policemen.

Mielke, 84, arrived in a wheelchair at Berlin Regional Court for the first session of his trial, which lasted 90 minutes to avoid taxing his strength. His lawyers had argued Mielke was too ill to go on trial, but doctors ruled otherwise.

Defense lawyers also argued the statute of limitations had long expired on the slayings, and that the original charge brought in 1933 did not offer Mielke the basic right to a fair trial.

Mielke was lifted from his wheelchair and carried to a seat behind bulletproof glass in the courtroom. Wearing a typically East German brown leather hat, he sat slumped in his chair.

A doctor attended to Mielke twice after he complained of not feeling well. ''I feel terrible,'' Mielke said, later adding: ''I can't stand it any longer.''

Police kept back hundreds of people drawn to what may be the biggest trial to come out of the collapse of Communist East Germany. Reporters jockeyed for position to get into the 90 seats reserved for the media.

About a dozen ultra-leftists carried signs saying ''Freedom for Mielke'' outside the courthouse.

Chief Judge Theodore Seidel, who presided at a recent trial that convicted two border guards of manslaughter for killing a man trying to flee over the Berlin Wall, adjourned the trial until next Monday.

The trial has curiously little to do with the hard-line Stalinist regime that Mielke served under party chief Erich Honecker.

Honecker, 79, is hiding in the Chilean embassy in Moscow. Unless he is somehow returned for trial as Germany demands, Mielke will be the highest- ranking East German official to face justice in Germany, which was united in October 1989.

During the last years of the Weimar Republic, Mielke was a young Communist in a self-defense organization that battled with the Nazis for control of the streets.

At 23, it is alleged, he and another man shot two policemen to death and wounded a third during a demonstration in front of Berlin's Communist Party headquarters on Aug. 8, 1931. Mielke fled to Moscow, and after Adolf Hitler took power in 1933, murder charges were announced against Mielke.

The Soviet KGB trained Mielke, and he returned to Germany after World War II to build the secret police in what became East Germany. In 1957 he became minister for state security - heading what was nicknamed Stasi in German - the job he held until communism collapsed in 1989.

Prosecutors are assembling evidence for more charges against Mielke related to the deaths of over 200 people killed trying to flee East Germany and support of Red Army Faction terrorists in West Germany.

Ironically, the 1931 murders might have been forgotten if investigators hadn't found the original prosecutor's file in Mielke's own Stasi office in 1990.