The Turkish gunman who shot Pope John Paul II testified today that the Bulgarian secret service had asked him to carry out other terrorist acts, including the assassination of Polish labor leader Lech Walesa and the leaders of Tunisia and Malta.

Giving evidence in the trial of his alleged accomplices in the papal plot, Mehmet Ali Agca also claimed for the first time that the Soviet Union had commissioned a rightist Turkish terrorist group to blow up the headquarters of the U.S.-financed radio station, Radio Free Europe-Radio Liberty, in Munich.

Agca said that the attack on the radio station, which broadcasts to the Soviet Bloc, was carried out in late 1980 but that he had not taken part.

Agca's claims of Soviet Bloc involvement in the attempted murder of the pope and other terrorist acts have not so far been substantiated by any other witness. The 27-year-old Turk again contradicted several points of his pretrial testimony and acknowledged making some "unfounded statements" to Italian investigating magistrates in the past.

The question of Agca's credibility as a witness has become a major issue at the present trial as a result of the zigzags in his testimony and assertion that he was "Jesus Christ."

Cross-examined by Judge Severino Santiapichi, Agca gave a fuller picture than previously of the structure of the Gray Wolves, a right-wing Turkish terrorist group with which he had links. He said he had associated with leading Gray Wolves in Western Europe in the months before the assassination attempt in St. Peter's Square on May 13, 1981, in between holding a series of meetings with Bulgarian officials in Rome.

Describing the purported plot to kill Walesa, who visited Italy in January 1981, Agca said that the Bulgarians wanted him to use a remote-controlled bomb to "eliminate" the leader of the Polish Solidarity union. The attack was to have taken place outside the headquarters of the foreign press association in Rome, where Walesa was giving a press conference.

The Turk told the court that the assassination attempt against Walesa, who was then at the height of his popularity in Poland, was called off because an unknown informer tipped off the Italian secret services and security was tightened.

In pretrial testimony, Agca said that the bomb attack against the Solidarity leader was to have occurred outside Walesa's hotel. In June 1983, he withdrew several details about the alleged plot. Investigating magistrate Ilario Martella later closed his inquiry into the matter on the grounds of lack of evidence.

Agca told the court that he had looked into the possibility of assassinating President Habib Bourguiba of Tunisia and former Maltese prime minister Dom Mintoff on the instructions of Maj. Zhelyo K. Vasilev, former assistant military attache at the Bulgarian Embassy in Rome and one of the three Bulgarian defendants. The attack allegedly was to have taken place in December 1980 during a visit to Tunisia by the Maltese leader.

"I didn't go through with the assassination attempt because the Tunisian police were too present," Agca said, after describing how he had scouted out the route outside Bourguiba's official residence in nearby Carthage.

Asked by Santiapichi about a Tunisian police report stating that he had met a Turkish emigre called Dag Youssef during his stay in Tunisia, Agca insisted that he had not met "any of my conationals in Tunisia."

Agca appeared to commit an error of timing in his description of the bombing Radio Free Europe -- which he said had been requested by "the Soviets" -- since no such attack was recorded in late 1980.

The Munich headquarters of the radio station was devastated by an explosion on Feb. 21, 1981, responsibility for which was claimed by a mysterious group calling itself the "Armed Secret Army."