SALZBURG, AUSTRIA, JULY 26 -- Czechoslovak leader Vaclav Havel admonished Austrian President Kurt Waldheim today that one must "look his own past in the face" and that "lies cannot save us from lies."

A beaming Waldheim welcomed Havel to the Salzburg Festival today but found that the price of contact with the Czechoslovak president and playwright was to sit through a probing address that went to the heart of the controversy surrounding the Austrian head of state.

Havel fulfilled a longstanding invitation to make the keynote speech at the start of the 70th annual musical event, despite criticism that he should have stayed away to avoid Waldheim. The Czechoslovak president said he kept the commitment "out of respect for this famous festival and the Austrian people."

Havel acknowledged he was going "against the stream" in meeting with the former U.N. secretary general, but he said before his arrival that the four-year-old boycott of Waldheim -- who covered up his wartime service in a German army unit involved in Nazi atrocities -- had become a senseless game that had turned Waldehim into a scapegoat.

Waldheim enthusiastically greeted Havel and West German President Richard von Weizsaecker, who accompanied Havel to the city of Mozart's birth, as dozens of photographers scrambled to document their initial encounter in the foyer of Festival Hall. Four U.S. protesters yelled out, "Shame for meeting Nazi Waldheim!" and were arrested and fined for public disorder. They included Rabbi Avi Weiss of Riverdale, N.Y., who led a protest last summer against a convent of Roman Catholic nuns at the Nazis' Auschwitz extermination camp in Poland.

Soon after Waldheim introduced Havel as "living proof that the explosive power of culture can be stronger than weapons and repressive force," the playwright-president declared that Central Europeans' fears about the future could only be overcome by telling the truth about the past.

"Whoever fears to look his own past in the face must necessarily fear what is to come," Havel said. "All too often in this part of the world, the fear of one lie only gives birth to another in the vain hope that salvation from the first one is a salvation from all lies. Lies cannot save us from lies."

"The supposition that one can walk the tightrope of history and rewrite one's own biography without being punished," Havel continued, "is one of the traditional crazy ideas of Central Europe. If anyone tries to do this, he only harms himself and his fellow citizens, for there can be no full freedom where the full truth is not given free rein."

Waldheim, who omitted references in his autobiography to his service as a German army intelligence officer in the Balkans, where thousands of Jews and resistance fighters were sent to death camps, sat stolidly through the speech, as did his wife, Elisabeth, who once belonged to the Nazi Union of German Maidens.

Waldheim long maintained that he left the German army after being wounded on the Russian front and returned to Vienna to complete his law studies. He has resisted calls for his resignation and has refused to rule out seeking a second term in 1992.

Asked by an Austrian state television interviewer whether he felt Havel's remarks were directed at him, Waldheim replied, "Certainly not. I did not rewrite my biography. I have denied nothing. I am aware of the historical context of my youth, like hundreds of thousands of other Austrians. It has been repeatedly proven by international commissions that I was not in any way involved in war crimes or other guilt."

Havel received a standing ovation after the address, delivered before the stone arches of an imposing former riding school modified for the festival's opera performances. The Czech Philharmonic opened the ceremony with Antonin Dvorak's "My Home" Overture and concluded with Mozart's Symphony No. 38, the "Prague" Symphony.

Later, Havel met Waldheim and Austrian Chancellor Franz Vranitzky to discuss Austria's growing anxiety over a Czechoslovak nuclear power plant near the Austrian border. Havel and von Weizsaecker then attended a lunch with Waldheim given by the provincial governor.

Havel returned to Prague after seven hours in Salzburg, where he also met with a group of prominent artists, including conductor Sir Georg Solti, tenor Placido Domingo and architect Hans Hollein. Von Weizsaecker, who made no public statement, also returned immediately to West Germany rather than staying on in Salzburg, where he would have been Waldheim's guest.

Both foreign leaders stressed that they came to Salzburg as private citizens and have not found time in their schedules to pay official visits to Austria.

Apart from President George Vassiliou of Cyprus, who paid a three-day state visit to Vienna earlier this month, Havel and von Weizsaecker are the first Western heads of state to meet with Waldheim since his election as president in 1986.