Fifteen American passengers from the hijacked Italian cruise liner Achille Lauro, among them the wife of the murdered Leon Klinghoffer, returned home here today to an emotional reunion with family and friends.

A family spokeswoman later said that Marilyn Klinghoffer told President Reagan that she spat in the faces of the hijackers during a stop in Italy where she identified the men for authorities.

Letty Simon, speaking for Klinghoffer, said Reagan replied, "You did? God bless you."

According to a White House spokesman, Reagan told her, "Nancy and I share your deep sorrow at this difficult time and are keeping you in our thoughts and prayers."

Reagan initiated a call to Klinghoffer shortly after she arrived at Newark International Airport.

She stepped from a brown and white airport bus into the midday sunlight to face scores of television cameras outside the Marriott Hotel.

Just hours before, Klinghoffer, 57, along with three other American hostages, had come face to face in Sicily with the Palestinian terrorists and identified them as her husband's assassins.

She seemed a brave if grief-striken figure, clad in black, red lipstick standing out against a drawn face.

Clutching a canvas beach bag, a sad memento of a cruise holiday that ended in the murder of her partially paralyzed 69-year-old husband, she paused briefly before the cameras. Then, leaning on several friends for support, she walked, almost as if in a trance, to meet her daughters, Lisa and Ilsa.

Minutes later, the other American hostages filed out of the bus from the airport, the last leg in a grueling journey that began in Cairo, some 16 hours earlier.

The hostages had flown in a C131 military transport plane, stopping off first in Sicily where four of the hostages, including Klinghoffer, identified their captors and then for refueling at the American Rhein-Main Air Base near Frankfurt.

Confirmation of the assassins' identification came at a news conference held by U.S. Ambassador Vernon Walters, accompanied by Sen. Alfonse M. D'Amato (R-N.Y.) and Sen. Frank R. Lautenberg (D-N.J.).

For two hours several of the hostages were closely questioned by FBI officials about their experiences on board the Achille Lauro. Walters said this debriefing was part of an effort to build the U.S. case for extradition of the four Palestinians. "We as a people do not seek vengeance," he said. "We seek justice."

D'Amato, who had just spoken to Klinghoffer, said, "She held up magnificently," adding that she had told him she was willing to go to Italy to testify against the Palestinians when they appear in court to face charges of murder and hijacking on the high seas.

D'Amato said Klinghoffer had expressed gratitude for the daring interception of the terrorists aboard the Egyptian airliner last Thursday. "Thank God the president did this," were her words, according to D'Amato.

Throughout the day the hostages' relatives had arrived in tightly knit groups, passing through a security cordon that included Secret Service men, bomb sniffer dogs and scores of New Jersey policemen.

Once reunited, most of the families shunned reporters and slipped away. But Frank Hodes, 66, whose wife, Mildred, was held captive, emerged briefly to speak on her behalf. He said he wished to deny reports that his wife had had a gun held to her head and had pleaded for her life.

"She was one of many Americans who were held in a room where it was contemplated that she be killed by these animals," Hodes said.

He also disclosed that only after his wife had left the ship did the captain of the Achille Lauro inform her that her passport was on top of a heap of American passports stacked in the order in which they were to be killed. He added that the Americans had been segregated from the Europeans and abused and harassed.

The Klinghoffer family came in a motorcade around midday, escorted by close friends to wait in a secluded room at the hotel. At 3:25 p.m. Klinghoffer and her daughters left, escorted by six police cars, on their way to the family's Manhattan apartment.