President Carter, in a remark that sparked speculation about possible U.S. retaliation against Iran, told congressional leaders yesterday that the release of the American hostages in Tehran will not "wipe the slate clean" at the end of the crisis in Iran.

The president, who has scheduled a nationally televised news conference for 9 o'clock tonight, made the comment in response to a question about what the United States would do if the 49 hostages eventually are freed unharmed.

White House officials moved quickly to dampen speculation about retaliatory moves by the United States, but not before Sen. J. Bennett Johnston (D-La.) said that, while Carter did not specify what action he would take, "All of us feel. . . that he will do something else after the hostages are released."

Johnston also quoted the president as saying that "the honor of the country" is at stake in the crisis, that preserving that honor is his "first concern" and that "there are conditions, prices for the release of the hostages that this country will not pay."

White House press secretary Jody Powell said that Carter's reference to what will happen at the conclusion of the crisis was merely "stating the obvious."

"Any fool knows that an incident like this will affect relationships after the hostages are released," he said.

The president met with the congressional delegation at the start of a busy day that also included these developments:

Attorney General Benjamin R. Civiletti, in a prepared statement, urged Americans to remain calm and not discriminate against Iranians in the United States "despite our justifiable anger." Civiletti hinted that the Justice Department might seek court orders to block instances of discrimination.

Congressional criticism of Rep. George V. Hansen (R-Idaho) private mission to Iran continued, but Hansen was supported by House Minority Leader John J. Rhodes (R-Ariz.). "He succeeded in contacting the Iranian foreign minister and he succeeded in contacting the American hostages," Rhodes said. "That is more than any other American has done." But House Speaker Thomas P. (Tip) O'Neilll Jr. (D-Mass.) said Hansen has "very little credibility" in Congress and that his mission to Iran was "a bad mistake."

House Banking Committee Chairman Henry S. Reuss (D-Wis.) said he has received support from other committee Democrats to conduct an inquiry into the activities of Iran's deposed shah, Mohammad Reza Pahlavi who is undergoing treatment for cancer in New York. Hansen has suggested that Congress pledge to investigate the shah's rule in Iran in an attempt to win release of the hostages.

The State Department urged Americans to avoid private travel to 11 moslem countries because of the Iranian situation. It listed the countries as Libya, Iraq, Syria, Lebanon, Kuwait, United Arab Emirates, Qatar, Oman, Bahrain, North Yemen and Bangladesh.

Carter canceled a political trip planned for Friday to Seattle, Wash., and Portland, Ore. It was the fourth out-of-town trip the president has canceled since the Nov. 4 takeover of the U.S. Embassy in Tehran.

At the White House yesterday, attention was focused on Carter's remarks to the Democratic leaders.

Speaking to reporters after the breakfast meeting, Johnston said that U.S. retaliation against Iran would not necessarily involve military action.

"There are a whole range of options I think that can be taken not necessarily involving military action," he said.

He said no one at the White House was intimidated by threats from Iranian authorities.

"The president said that his first concern was the honor of this country," Johnston said. "He didn't say that in a way that would show less concern for the hostage, but there was a real resolve on his part. . . that we not do anything to sully the honor of this country by negotiating for hostages, negotiating away the honor of the country."

Powell yesterday refused to rule out possible U.S. retaliation however the embassy takeover is resolved. But he insisted that Carter's remarks to the congressional delegation involved only the overall impact of the crisis on U.S.-Iranian relations.

Privately, it has long been assumed by officials that the president will order some sort of retaliatory steps against Iran even if the hostages are freed unharmed. But there has been no public discussion of this because it would likely only complicate the task of freeing the hostages.

It was thus surprising Carter, who, according to Johnston, raised the subject of Iran himself, would make any kind of reference to that possibility. s

Powell noted that the comment came during a private meeting. But congressional leaders almost always talk to reporters after meeting with the president, frequently quoting him and giving their impressions of his intentions.

Carter will almost certainly be faced with difficult questions at tonight's news conference, the timing of which also was surprising, given the explosive situation in Tehran. Powell said the news conference was scheduled because " the president felt the American people deserved an opportunity to hear from him."

However, there are other possible benefits for Carter in the news conference. With the nation's attention riveted on Iran, the president is guaranteed a massive audience as he explains his handling of the crisis, an obvious political plus.

Moreover, it will provide Carter with an opportunity to underscore personally the administration's repeated statements to Iranina authorities that the United States will not back down from its demand that the hostages be freed.

In another deveopment yesterday five men, four of whom claimed to be members of Vietnam Veterans Against the War, stormed into Selfridge Air National Guard Base at Mount Clements, Mich., demanding that the United States "keep your bloody hands off Iran." The five were arrested. Outside the airbase, about 25 protestors also demonstrated against U.S. acton against Iran.

Reuter news service reported the following :

In a meeting yesterday with New England community leaders, the president said the hostages had been punished for speaking, and had been threatened at gunpoint.

"tThe hostages are not being trated well," Carter said. "They have been kept bound now, with hands and feet tied, for 23 days.

"They have not been permitted to speak a word. When they have spoken, to say "good morning" or good luck," they have been punished.

"They've been treatened at times at pistol point and encouraged to make statements contrary to their own inclination," Carter said.

Reporters were not permitted to attend the meeting. Carter's remarks were taken from a tape recording made by one of the guests.

Carter compained that the hostages had not been permitted to leave the embassy, and had not been allowed to take baths or change clothes since they were seized on Nov. 4.

"This is a reprehensible thing, a disgrace to every person who believes in civilization or decency,' he said.

"We have two major commitments: to protect the honor of our country and to stand for basic principles that are unshaken," he said.

"Another, of course, is to work as best we can. . . for the safety and release of the hostages. . . I will protect the honor of our country and not under any cirmustances yield to blackmail."