Italian investigators focused their attention today on possible links between accused papal assailant Mehmet Ali Agca and international terrorist organizations as Pope John Paul II continued to make progress in recovering from his gunshot wounds.

The Gemelli Hospital, where the pontiff is being treated in the intensive care unit, issued a bulletin tonight saying that "the day has been characterized by steady improvement in the health of the Holy Father. No variations worth noting were seen in the clinical picture."

Magistrates who have been questioning the 23-year-old convicted Turkish terrorist since his arrest Wednesday in St. Peter's Square after the shooting reportedly are convinced that he received help in obtaining money, forged identification documents, a pistol and ammunition.

Deputy State Prosecutor Luciano Infelisi, who reportedly chatted informally with Italian reporters last night, was quoted in Italian papers today as saying there was "documented proof" that Agca "is a killer who was engaged by an international group for subversive purposes.

But tonight, interviewed on television, Infelisi said that this is largely only a working hypothesis, although, in the investigators' minds, a credible one. Because of the Turkish suspect's well-financed and extensive travels, he said, "we have ruled out the theory that this was a gesture of an isolated madman," but he said that he still was "not convinced" that there was an international conspiracy.

Nonetheless, he said, because of the help Agca apparently had in his travels and because witnesses to the shooting said they saw other people who seemed to be associated with him, the charges against the prime suspect had been extended to include "other unknown persons."

[Police brought two students to Rome from Perugia, where Agca enrolled in April for language classes, because they had once talked with him, United Press International reported. But questioning "failed to provide any useful elements," police said. ABC-TV news said a Turkish student from Perugia had been arrested, but there was no independent confirmation of this report.]

Meanwhile, bulletins from Gemelli Hospital said the pope continued to improve and that his vital signs were largely normal. A morning report from the hospital said his blood pressure was "being maintained within 140-80. The heart rate is between 90 and 110 beats per minute with normal sinus rhythm. The respiratory frequency is maintained at 18 breaths per minute with excellent oxygenation."

Earlier in the day, the hospital's director, Dr. Luigi Candia, said that the pope's pain was somewhat diminshed and that his morale was high.

Doctors emphasized, however, that the danger of abdominal infection was still high. To minimize that risk, the pope was being kept in a glass-walled isolation cubicle, which meant that most of his visitors could view him only from a distance and speak to him through an intercom system.

John Paul was still being fed intravenously, doctors said, as his wounds healed. The bullets from the 9mm Browning pistol shattered his left index finger, inflicted a flesh wound on his right arm and severed his colon. The latter injury, by far the most serious, led to nearly four hours of abdominal surgery Wednesday.

Early this morning, the pope's personal secretary, Msgr. Stanislaw Dziwisz, read aloud to John Paul, at his request, from the breviary -- a book containing prayers to be said daily by Roman Catholic priests. According to a Vatican press spokesman, Father Romeo Panciroli, "The pope was very attentive and followed the prayers with movements of his lips."

Preparations at the hospital suggest that the pope hopes soon to be well enough to conduct some business from his sickbed. As soon as his vital signs are fully stabilized and the threat of infection has lessened, he is expected to be moved to an apartment being readied in the hospital.

Two Americans wounded in the attack on the pope also continued to improve today, although one of them, Ann Odre, of Buffalo, N.Y., was still reported in serious condition with abdominal wounds. Rose Hall, living in Wuerzburg, West Germany, was reported in good condition with an arm wound.

With the pontiff seemingly out of immediate danger, attention here has focused on investigators' attempts to reconstruct Agca's movements over the last month and to try to discover how he was being financed.

According to police sources, the suspect, who escaped from a prison in Turkey, where he was sentenced to death for the murder of a prominent editor, was somewhat more relaxed today after abandoning a hunger strike that had lasted just one day.

The sources said Agca (pronounced AHD-ja) continued to insist he has ties to the Palestinian movement, a claim denied by Palestinian officials in Beirut yesterday. Agca reportedly claimed he had been trained in Palestinian camps, but backed off when the examining magistrates asked for specific details.

The Rev. Hilarion Capucci, former Greek Catholic archbishop of Jerusalem who was imprisoned by Israel on charges of smuggling weapons to Palestinian guerrillas, went to the Gemelli Hospital today and told reporters that Agca was lying when he claimed to belong to a Palestinian organization.

"What he did had nothing to do with Islam," Capucci said. "This Turk is a criminal of the far right."

Turkish authorities have said Agca was a member of an extreme right-wing organization.

Agca, after repeated questioning about the money he has spent on his travels, reportedly has told investigators that since his escape from Turkey in late 1979 he has received $10,000.

Agca gave no details. But the investigators have formulated the theory that his travels through several European countries may have been related to dropoff points for money. Police experts have calculated that his underground existence must have cost about $100 a day.

It was confirmed today that Agca briefly visited Sicily on Dec. 13, but there was no indication of the purpose. His next documented appearances in Italy were Jan. 19 and Jan. 28 to 30, both in Rome. In early February a caller told the Turkish consulate in Milan that Agca was at a downtown restaurant. When police arrived, there was no trace of Agca.

Agca next appeared in Rome and Perugia in early April and returned to Milan on April 23 and went immediately to the neighboring town of Cuneo, where for about $450 he purchased a round trip charter ticket to the Spanish island of Majorca.

Reportedly traveling, as usual, under an assumed name, he returned to Italy two weeks later and was in Rome on May 9. Although they gave no details, police said tonight they now are able to account for his movements in Rome through the 13th, the day he allegedly attempted to assassinate the pope.

Agca reportedly has said he got the 9 mm pistol in Bulgaria, although he gave no details. Police sources said tonight the gun had been traced to a Belgian factory whose owners were cooperating in tracing its history. Police say they think Agca brought the gun into Italy in April by train from Switzerland and checked it at a luggage deposit in Rome until last week.