Buoyed by the weekend's calm in Iran, President Carter offered Shah Mohammed Reza Pahlavi firm new public assurances of U.S. support yesterday while reiterating that his administration will not permit "others to interfere in the internal affairs of Iran."

Speaking at a news conference, the president did not name the warning's obviously intended target, the Soviet Union. But an authoritative source reported that the comment was made against the background of an exchange of stiff private messages about Iran between the United States and the Soviet Union.

Asked about the report, a spokesman for the National Security Council said the White House did not comment on the contents of diplomatic exchanges.

Carter's relatively brief remarks on the nearly year-old Iranian crisis of authority sent ripples elsewhere as well. They failed to bridge splilts within the administration over U.S. policy and they focused attention on Frances's role in allowing the shah's principal political foe to live in France and issue what Carter called "uncontrolled statements . . . that encourage blood baths and violence.

The policy debate within the administration will probably sharpen today when George W. Ball submits a report on U.S. policy options in the Persian Gulf to the presidenths national security affair adviser, Zbigniew Brzezinski.

An NSC spokesman said last night that the report was "an internal document for the president" and there were no plans to announce its completion. Ball, undersecretary of state in the Kennedy and Johnson administrations, has been conducting a study on current U.S. policy on Iran.

Carter sparked fierce anxiety in Iran and among the shah's supporters in Washington last Thursday by responding to a question on whether he thought the shah would survive by saying, "I don't know. I hope so. This is something that is in the hands of the people of Iran."

He clearly sought yesterday to remove that equivocalness from the record.

"I fully expect the shah to maintain power in Iran and for the present problems in Iran to be resolved," he said. Expressing relief that "the predictions of doom and disaster" that preceded last weekend's massive demonstrations "have certainly not been realized at all," Carter added: "The shah has our support and he also has our confidence."

Carter's failure to give the shah's political opponents any credit for keeping the demonstrations peaceful reinforced the position of those in the administration who argue for total public support for the shah.

Other policymakers and analysts fear that the shah may now conclude that the crisis is over and that he does not need to move toward a power-sharing arrangement with the opposition.

The effort to reassure the shah and to firm up the administration's public posture began almost immediately after Carter's equivocal remarks Thurday and reflect the fissures within the administration on Iranian policy, according to reliable sources.

Brzezinski reportedly has been urging the strongest possible public display of support for the shah. Openly concerned that Thursday's remarks might be seen as a weakening of U.S. resolve, Brzezinski is reported to have telephoned Ardeshir Zahedi, the Iranian ambassador to Washington, with reassurances of support shortly after the president made the remarks.

The White House has confirmed that Brzezinski spoke to Zahedi on Friday after news accounts of the remarks reportedly upset the president, but there has not been official confirmation of the Thursday conversation.

On Friday the White House directed the State Department to deny that the president's remarks represented any change in policy. A White House aide said last night that the "amplification" had been triggered by "too strong an interpretation in news stories."

In another semantic exercise, Carter appeared to toughen slightly his generalized warning against intervention in Iran. Yesterday, he volunteered that "we have no intention of interfering in the internal affairs of Iran and have no intention of permitting others to interfere in the internal affairs of Iran."

At this Nov. 30 news conference, Carter said that "we do not approve of any other nation interfering in Iran; at Thursday's breakfest he omitted any such warning.

The United States struck a firm tone in responding earlier to a public challenge from Soviet party leader Leonid Brezhnev against U.S. involvement in Iran. But the White House reportedly has fresh cause for concern because of stiff private exchanges between Washington and Moscow.

Carter yesterday implicitly attacked Ayatollah Ruhollah Khomeini, the exiled leader of Iran's conservative Moslems who have been the spearhead of the protests against the shah. Although he did not mention the 78 year-old Moslem leader by naem, U.S. and diplomatic sources said Carter clearly had him in mind when the president said:

"The difficult situation there has been exacerbated by uncontrolled statements made from foreign nations that encourage blood baths and violence. This is something that really is deplorable and I would hope would cease after this holy season passes."

The shah sent Khomeini into exile in Iraq in 1963, and last September the ayatollah was expelled from Iraq to Paris, where he has given frequent interviews and issued public calls for the army to overthrow the shah.

French and U.S. officials said yesterday that neither Iran nor the United States had complained officially to France about Khomeini's presence there or about his statements. French authorities have formally warned Khomeini three times about speaking out on Iran while he is in France on a tourist visa, but they have taken no further action. In the past, lesser-known political activists have been summarily expelled from France for less intensive activity.

Khomeini's French visa is due to expire at the end of the month, about the time that the holy Moslem mourning month of Moharram finishes.

The shah may feel that pushing France to silence Khomeini would add to the ayatoolah's political stature at home, diplomatic sources said. A spontaneous French move to silence him would probably expose French interests in Iran to hostile mob action, the sources added.