Federal officials yesterday vowed to conduct a worldwide effort to capture the suspected mastermind of the hijacking, Palestine Liberation Front leader Mohammed Abbas, who was released over the weekend by Italian authorities despite a U.S. arrest warrant issued against him.

Attorney General Edwin Meese III labeled Abbas "an international criminal" and said the United States would do everything possible to capture him, including use of military force if circumstances are right.

The Justice Department, meanwhile, has charged the four hijackers of the Italian cruise ship Achille Lauro with piracy, hostage-taking and conspiracy, even though federal officials acknowledged yesterday that it is unlikely that the pirates will be extradited from Italy to stand trial in the United States.

Abbas was captured Thursday night with the four hijackers when the Egyptian 737 airliner in which they were flying was forced to land on Sicily by U.S. Navy jet fighters. He was later allowed to fly to Yugoslavia, and there were reports yesterday that he had left Belgrade for an unknown destination.

U.S. District Court Judge Charles R. Richey signed arrest warrants late Saturday against Abbas and the four Palestinian hijackers in a meeting with federal prosecutors at his Chevy Chase home. The warrants were based on an affidavit outlining the government's evidence, which remains sealed because it contains sensitive intelligence information, according to federal sources.

So far there has been no sign of the evidence the United States says it has gathered to support the charge that Abbas was intimately involved in directing the hijacking of the Achille Lauro.

A source in the intelligence community who reviewed the sealed allegations against Abbas said the U.S. government appeared to have evidence that Abbas participated in the planning of a half-dozen terrorist attacks against Americans.

"This was a bad-news guy," the source said. "He basically was involved in planning other hijackings of Americans and we had enough to arrest him and hold him for a hearing."

On Friday night, Richey initially had approved an arrest warrant against Abbas in a telephone conversation with Justice officials, who were mounting an unsuccessful attempt to persuade Italian authorities to detain Abbas.

Federal authorities say they have evidence that Abbas was involved in the plot that led to seizure of the ship, although Abbas has insisted that his role was confined to negotiating the hijackers' surrender.

Abbas was quoted in a radio interview as saying the hijackers were traveling to an Israeli port on a "suicide mission" and seized the Italian ship only after their plans went awry.

State Department legal adviser Abraham D. Sofaer said yesterday that the evidence against Abbas relies heavily on transcripts of intercepted radio communications between Abbas and the hijackers aboard the ship. "They obeyed his orders," Sofaer said.

"The evidence we have right now is that he participated in all of this, guiding them throughout," a Justice Department official said of Abbas.

The criminal complaint charges that Abbas and the four Palestinians -- identified as Hallah Abdalla Al-Asan, Maged Yussef Al-Malaki, Hammad Ali Abdullah, Abdel Atif Ibrahim Fatayer -- "did knowingly, willfully and unlawfully seize and detain . . . and threaten to kill, injure and continue to detain nationals of the United States who were passengers on the cruise ship Achille Lauro . . . ."

The complaint said their purpose was "to compel . . . the state of Israel to . . . release 50 Palestinians held in Israel." The primary statute cited is the hostage-taking section of a 1984 crime control act, which carries a maximum penalty of life in prison.

Despite the charges, it is unlikely that the hijackers will face trial here if the Italians press ahead with prosecution, Justice officials said. Italy has charged the four Palestinians with kidnaping, hijacking and the murder of ship passenger Leon Klinghoffer, 69, of New York.

Secretary of State George P. Shultz, speaking to a NATO meeting in San Francisco yesterday, said the killing of Klinghoffer "tells us something about terrorists: they're animals, cowardly animals. These are not guerrillas. These are not fighters for some liberation movement. They select the helpless for torture and murder.

"They lack the guts to do battle just as they lack the guts to seek justice and peace by negotiation . . . ," the secretary said to resounding applause from the 184 assembly delegates.

Experts say the U.S.-Italian extradition treaty bars prosecution in both countries for the same acts. "If the Italians go ahead and prosecute, there's no way Italy could extradite to us under the treaty," said Michael Abbell, former director of the Justice Department's Office of International Affairs.

Federal officials said Italy breached the treaty by letting Abbas go. They said the treaty requires Italy to hold a suspect sought by U.S. authorities for up to 45 days pending hearings on the request, but Italian officials unilaterally decided to release Abbas, on grounds of insufficient evidence.

Yugoslavia also refused to detain Abbas, and the State Department said it would be "extremely upset and disappointed if he has left Yugoslavia." Abbas could travel to a number of countries -- including Jordan, Syria, Lebanon and Iran -- that have no extradition agreement with Washington.

Meese scoffed at Abbas' offer to appear before U.S. authorities if he was guaranteed safe passage through the country. "It's important that he be brought back to answer for his crimes and not be given immunity so he can engage in a propaganda campaign," Meese said on "CBS Morning News" yesterday.

Asked if the United States would use military tactics to capture Abbas as it did to seize the four gunmen, Meese did not rule it out, saying, "It all depends on the circumstances."

FBI officials said they have dispatched two teams of agents to Italy to assist in the investigation, and that a forensic team is expected to examine evidence aboard the Achille Lauro.

FBI agents also are interviewing former ship passengers in New York and gathering evidence in case the hijackers can be tried here. FBI Director William H. Webster said the bureau will work with Interpol and other international groups in pursuing Abbas.