The Turkish gunman who shot Pope John Paul II testified today that he had tried to secure U.S. support after he began talking to Italian investigators about a "Bulgarian connection" to the papal assassination attempt.

Mehmet Ali Agca, who was sentenced to life imprisonment in July 1981 for trying to murder the Polish-born pontiff, told an Italian court that he had been hoping to win his freedom as a result of an East-West political deal or exchange. He was replying to questions about why he had written a letter to the U.S. military attache in Rome in August 1983.

Agca's testimony today provided some insights into his erratic behavior during the three-year pretrial investigation.

Under cross-examination by the court, Agca continued to contradict parts of his earlier testimony about his alleged Bulgarian and Turkish accomplices.

Judge Severino Santiapichi pressed the 27-year-old Turk to explain why he had written a letter to the U.S. military attache in Rome that gave the impression that the two of them were close collaborators. In the letter, which was written in Turkish and slipped past prison censors, Agca told the U.S. official: "You told me to talk, and I talked."

Acknowledging that he had never had any dealings with the American military attache, Agca said he thought that the letter would put pressure on the U.S. administration to help him and even provide him with U.S. citizenship. He said he hoped the letter would be published in the press, but then his explanation became confused.

"The American Embassy does not get involved in cases as big as this, but someone from the White House was involved, if you think about it. This is the truth," he said.

Agca's remark about the White House was not explored by Judge Santiapichi, who apparently has become accustomed to wild claims from the prosecution's star witness in the four-week-old papal conspiracy trial.

Later on, Agca said he had hoped for an exchange of prisoners between Italy and Bulgaria and his own "extradition" to the Vatican. He presumably believed that the Vatican would set him free, since he has already been pardoned by Pope John Paul II.

"I was acting according to conditions outside prison . Let's say I was playing a double game," he told the court after boasting earlier in the session that he was "an expert in psychology."

The judge described Agca's hope for extradition to the Vatican as "a legal impossibility" and spoke scornfully about the Turk's belief that he might have received U.S. citizenship.

"After a letter like this one, if they had given you any sort of citizenship, they would have given it to you at San Quentin, or else hanged you from a public place," he said, jokingly.

In the August 1983 letter to the U.S. military attache, which was turned over to Italian magistrates by the embassy, Agca made half a dozen "suggestions" for "future collaboration." They included blaming the then-Soviet leader Yuri Andropov for the attempted assassination of the pope and finding credible witnesses to testify against Bulgaria.

The letter has been cited by the Soviet Bloc media as evidence that western secret services encouraged Agca to implicate Bulgaria in the assassination attempt.

Agca also gave confusing testimony on what happened to the $1.2 million reward allegedly offered by the Soviet secret service for the assassination attempt. No trace of the money referred to by Agca ever has been found.

The trial continues on Monday.