The Rev. Lawrence M. Jenco, the American Catholic priest released Saturday after being held captive in Lebanon for almost 19 months, flew here this evening for a private meeting Wednesday with Pope John Paul II to deliver a message from his Shiite Moslem captors.

The 51-year-old priest, who was released in Lebanon's Bekaa Valley and then flown to West Germany the next day for a medical checkup, told reporters on arriving at Rome's Ciampino airport that he would also discuss with the pope the plight of the three Americans still being held by his captors.

Jenco is scheduled to meet with John Paul before the pope's regular Wednesday public audience.

Looking tired but expressing delight to be back in the city of his ordination, Jenco said that "before I left Lebanon . . . my captors asked me to speak to him the pope ."

He declined, however, to discuss details of the message from his kidnapers, who are members of the pro-Iranian Lebanese Shiite group Islamic Jihad (Holy War). Jenco said the pope, not he, would determine whether the message will be made public.

Jenco was ostensibly released because of "failing health" and, according to a message from Islamic Jihad to news agencies in Beirut, as a final gesture to encourage the United States to negotiate for the release of the remaining American hostages.

Islamic Jihad has indicated in the past that it wants a number of Shiites being held in Kuwait in connection with a bombing attack on the U.S. Embassy there to be freed in exchange for the American hostages.

The U.S. government has repeatedly said it would not negotiate with the kidnapers.

Jenco's message today was not political.

"I'm just very happy to be here," Jenco said in a soft voice. "I was ordained in Rome in 1959 and celebrated my 26th anniversary as a priest in captivity. It's just kind of nice to be present in the Holy City."

Wearing a "Free the hostages" button on the lapel of his clerical suit, Jenco, and 12 members of his family, were flown to Rome tonight on a U.S. Air Force jet from Frankfurt, West Germany, where he had spent two days undergoing medical tests at the U.S. Rhein-Main Air Base.

Also on the plane was Terry Waite, a representative of the archbishop of Canterbury who has made several trips to Lebanon in the past year to try to secure the release of foreigners being held there.

After Jenco's meeting with the pope, Waite will escort him to Britain to meet with the archbishop of Canterbury, Robert Runcie.

Before leaving West Germany today, Jenco said he hoped to be a personal envoy to the families of the three Americans with whom he shared part of his imprisonment.

Speaking publicly through the press to his captors, Jenco asked them to communicate to those still in captivity that he will be visiting their families.

Jenco's fellow hostages are Terry Anderson, 38, the Middle East correspondent for the Associated Press; Thomas Sutherland, 55, dean of agriculture at the American University of Beirut, and David Jacobsen, director of the university's once renowned hospital in Beirut. Islamic Jihad claimed last October to have executed hostage William Buckley, a U.S. diplomat.

The Associated Press reported the following from Boston:

Terry Anderson's sister returned to the United States after two weeks in the Middle East lobbying political leaders in an effort to gain his freedom. Peggy Say said Syrian leaders were receptive to her pleas for help. Say said she learned that, like Jenco, Anderson wore leg chains and had not received news of the deaths of his father and brother.