The United States provided secret equipment to Egyptian commandos preparing to storm a hijacked jetliner on Sunday and also offered to protect the commandos with warplanes from the USS Coral Sea, Pentagon officials said yesterday.

The Egyptian force was given what U.S. officials described as "technical support," including portable listening gear which allowed the commandos to determine where the terrorists were located inside the hijacked Boeing 737. Sixty people were killed during the rescue attempt.

The Coral Sea had been ordered to have F/A18 fighter bombers and E2C control planes prepared for action if the Egyptian government requested help in protecting the C130 transport planes carrying the commandos, Pentagon officials said. The Egyptians never asked for help.

An administration official said the quick offer of U.S. military assistance is part of a "get tough" policy on terrorist attacks, with the United States prepared to help friendly governments requesting aid against terrorists.

Pentagon officials added, however, that the offer of armed assistance did not extend to bombing missions against Libyan forces if any military action had been taken against Egypt during the hijacking crisis. "That's not our bag," one official added last night.

The White House said yesterday that President Reagan had sent a message of support to Egyptian President Hosni Mubarak for the decision to dispatch the commandos to Malta.

According to spokesman Edward Djerejian, Reagan sent the cable to Mubarak Sunday night through the U.S. Embassy in Cairo. The White House declined to reveal the contents of the message, but one official said it supported Egypt's handling of the rescue attempt while lamenting the loss of life.

Defense Secretary Caspar W. Weinberger also praised Mubarak for his action, in an interview with Reuter news agency, saying "we think the Egyptian and Maltese governments did what had to be done."

The State Department reaffirmed that the United States "fully supports" what it called the "difficult decision" taken by the governments of Egypt and Malta to storm the Egyptian airliner.

"Rescue operations like the one undertaken at Lucca [on Malta] are risky affairs, undertaken only in extreme circumstances," said State Department spokesman Charles Redman.

U.S. officials appeared anxious to avoid criticizing the high death toll or saying anything that could undermine Mubarak's position at home or abroad

Redman refused to comment on reports that the security lapse allowing arms to be smuggled aboard the Egyptian airliner may have occurred in Cairo rather than at the Athens airport. He said only that the United States was continuing to monitor the situation and to offer assistance for an investigation into how the hijackers boarded the plane with their weapons.

Redman said that there had been regular security checks at Athens airport since the United States lifted its travel advisory warning Americans to avoid the airport following the June hijacking of a Trans World Airlines jet.

"There have been regular follow-up inspections with no finding that overall security standards had declined," he said.

Redman also announced that the State Department was offering a reward of up to $250,000 for information leading to the arrest and prosecution of Mohammed Abbas, the Palestinian mastermind behind the seizure of the Italian cruise liner Achille Lauro in early October.

Asked about reports that Abbas was now in Baghdad attending a meeting of the Palestine Liberation Organization (PLO), Redman said the State Department had no information regarding his whereabouts.

The State Department and Pentagon also confirmed yesterday that the American woman killed by the hijackers, Scarlett Marie Rogenkamp of Oceanside, Calif., was a civilian U.S. Air Force employe at the Tanagra Air Base near Athens who was on vacation at the time of the hijacking.

The dead woman's sister, Katherine Petterson, said in Oceanside that her father had telephoned from Washington yesterday to confirm Rogenkamp's death and to ask that arrangements be made for a funeral Friday in California.