The federal appeals court here ruled yesterday that U.S. citizens who were held hostage for 15 months at the American Embassy in Iran cannot bring lawsuits for damages against the Iranian government.

A three-judge panel of the U.S. Court of Appeals unanimously upheld an order signed by President Carter -- part of a negotiated agreement that secured the hostages' release -- that precluded any court claims against Iran by the hostages or their families.

Judge Robert H. Bork, writing for the panel, said that while Congress had not specifically given the president the power to block the hostages' claims, it had taken no action to disapprove the agreement, reached in January, 1981. In effect, this approved Carter's decision, the court said.

"Strong presidential authority in the field of claim disposal, when necessary to the imperative interests of the nation, is, we believe, what Congress has approved," Bork wrote, citing similar cases in which Congress acquiesced in such decisions.

Bork wrote that in circumstances such as the Iranian hostage crisis, in which secrecy and quick action often are demanded, it would be "utterly impracticable" for the president to try to negotiate simultaneously with Congress and a foreign government.

"We find nothing in the Constitution that mandates any such stultifying and possibly disastrous result," Bork said in his opinion, in which he was joined by senior Judge David L. Bazelon and Judge Harry T. Edwards.

Bork, in a footnote, stressed that the court was referring only to presidential action within a range that realistically would be expected to have congressional approval.

The appeals court ruling upheld a lower court decision dismissing a lawsuit brought by Marine Sgt. Gregory A. Persinger of Seaford, Del. -- who had been a guard at the embassy in Tehran -- and his parents.

In the months after their release, many of the hostages and their families brought lawsuits against the Iranian government, several of which have been dismissed by lower courts.

The appeals court judges said the hostages and their families could take their cases to a special court in Washington that hears claims against the U.S. government and try to prove that the government illegally deprived them of compensation for injuries they may have suffered in Tehran. The appeals court judges emphasized, however, that they were taking no position on whether there was any merit to that claim.