President Carter, in an interview made public yesterday, said the United States is not considering new military measures to free the American hostages in Iran, but his press secretary insisted that this does not mean that force will never be used.

In an interview, Thursday with two European journalists, Carter was asked whether military measures against Iran are being excluded "for the time being" or have been foreclosed entirely.

"Military measures are not being considered," the president replied.

Carter's response, which did not directly answer the question, appeared intended to reassure European leaders, who were upset by the aborted American rescue attempt in April and have urged the United States not to use military force to try and end the stalemate.

However, White House press secretary Jody Powell, when asked about the president's statement, said it "simply meant that military measures are not being considered now."

"Those [military] options still remain and will be used, reluctantly, if necessary," Powell added.

The president, who granted the interview in connection with a weeklong trip he will make to Europe beginning in Italy on Thursday, said the United States is "pursuing every avenue -- through religious leaders, through private citizens, through the United Nations and through other governments -- to induce Iran to release the hostages so that normal relationships can be restored."

Calling on U.S. allies to "join in with us to convince the Iranians that they are making a mistake," Carter said:

"Now I think the best avenue is through a multitude of diplomatic and economic efforts being made through the United Nations and through other countries to convince the Iranians that it is counterproductive for them to continue to hold these innocent people."

While the president spoke of diplomatic efforts to free the hostages, Powell conceded that none of these initiatives has "borne fruit, nor do they seem likely to soon."

However, Secretary of State Edmund S. Muskie, in a news conference yesterday, suggested that release of the hostages could take place once political authority in Iran becomes more concentrated and once "Iran begins to perceive it has other, overriding priorities which it ought to be concentrating on and pursuing."

Muskie said there seems to be a growing awareness in Iran that the continued holding of the 53 hostages "is more of a problem than an opportunity." But he said efforts to win their release have been hampered by the diffusion of political authority in Iran.

While in Europe, Carter is to attend the annual economic summit conference in Venice with leaders of Canada, Japan and U.S. allies in Europe. U.S. relations with its allies have been strained recently because of differences over the Iran crisis, the Soviet invasion of Afghanistan and the process to achieve peace in the Middle East.

Nonetheless, the president insisted that the western alliance has never been stronger and said the United States understands when its allies sometimes disagree with it.

"Sometimes they don't support us strongly enough, as judged from our perspective, but we recognize the differences that must exist between us," he said. "I am sure that sometimes some of our actions are not completely pleasing to our allies."

Asked about the decision of European leaders to launch their own "fact finding" mission in the Middle East, Carter said the United States would welcome "constructive" steps by the Europeans but warned that anything that undercut the peace process begun by the Camp David accords would be "a very serious mistake."

On Soviet-American relations, the president said an improvement in the relationship is "up to the Soviet Union," which he said must withdraw its troops from Afghanistan.