Calling them "modern-day American heroes," President Carter yesterday welcomed the members of the U.S. Winter Olympic team to the White House, and said he regretted the United States would not take part in the Summer Olympics in Moscow as well.

The joyous occasion was clouded by the probability that the athletes' brother and sister Olympians would not be competing in the summer Games. One of the winter athletes, speed-skater Eric Heiden, winner of five gold medals, later told reporters "almost everybody" on the team had signed "a paper" expressing "our opinions on the boycott -- of the summer Games -- that we don't think it's the right thing to do."

Carter said at the ceremony he regretted that "the Soviet invasion of Afghanistan has voilated peace and the spirit of the Olympics and caused us to make a motion that the summer Olympics be moved or postponed." None of the athletes spoke at the ceremony.

Heiden told reporters that some of the Olympians felt he might have an opportunity to speak to the president about the boycott. But, said Heiden, he had not mentioned the subject to Carter. Last night, one of two officials of the U.S. team who circulated the petition said that 70 of the 120 members of the team had signed it and that it would be mailed to the president today.

Carter said at the ceremony, "You hear it said that there are no heroes. But our Olympic athletes are heroes."

Flanked by such members of the U.S. team as Charlie Tickner, Mike Eruzione, Leah Poulos-Mueller, Eric and Beth Heiden, Linda Fratianne and Him Craig, Carter added:

"As president of the United States of America this is one of the proudest moments I have ever experienced. I am deeply grateful for your tremendous achievements."

Member of Congress also saluted the team yesterday. Thomas Downey (D-N.Y.) compared the hockey victory to Charles Lindbergh's flight over the Atlantic Ocean, and Rep. Ike Skelton (D-Mo.) said, "They make all of us as Americans proud of them."

House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) called the hockey team's victory "a great lift to the American people, and it goes beyond that. There is nothing the Soviets appreciate more than sports -- it is their one area of freedom -- and their biggest sport is hockey.And now with the United States boycott you can believe me, heads will eventually roll in Russia."

Carter singled out each American medalist for special commendation. He said of speed-skating bronze medalist Beth Heiden, who had been widely touted for a gold: "My heart went out especially to Beth Heiden" before hugging her for what must have been the third time in the ceremony.

Of the U.S. hockey team's gold medal and victory over the Soviet Union, he said, "It was one of the most breathtaking upsets, not only in the Olympics, but in the entire history of sports." Of Linda Fratianne, "This is Linda Fratianne, isn't she beautiful?" before giving her still another hug and kiss. And of Eric Heiden, whom he embraced, holding him close and holding him up as an example of American heroism, "Your performances will be remembered for years to come."

Heiden said he had been warned "by some member of the Olympic committee" that some reporters might ask him political questions about his meeting with Carter.Heiden said he considered the visit to the White House "an honor," but he allowed that "it is an election year, and I guess we're all old enough to vote."

Heiden said he didn't like to mix politics with sports. But when he was asked if he thought the president was right in calling for a boycott, he said, "Oh, wow. I don't know. I think it'll probably be a big blow to the Russians, but it'll have an effect on the Americans, too." Of a boycott, Heiden said, "I hope we don't."

The drive to put together a petition to the president began over the weekend, after Carter invited the Olympians to the White House. The petition move was coordinated by two U.S. Olympic officials who were in Lake Placid to act as liaison between the athletes and other officials. One of the officials, Rick Colella, contacted at his home in Seattle last night, said that the petition had not been presented to Carter yesterday because signatures were still being collected.

"Time was so short and we had so little idea of what was going to go on at the White House that we never got totally organized." After Heiden's remarks, however, Colella gave the petitions to the other official, Suna Murray, to be mailed to the White House today.

"The petitiion says a lot of the same things the president said today," Colella said."It thanks the president for the invitation to the White House and talks about the importance of the Olmypic Games and the Olympic spirit."

Colella said the petition goes on to say: "there is no substitute for the Olympic Games. They do not belong to one country, but to the world. We urge you to do all you possibly can to let the summer Olympic athletes enjoy the same Olympic experience that we, the members of the winter Olympic teams, have enjoyed."

Colella added that none of those who signed the petition disagreed with President Carter's stand on Afghanistan in any way. "This isn't a political thing at all," he said. "We're just trying to say something that might help the other athletes."

Colella said a number of the athletes, however, declined to sign the petition.

"I didn't sign anything," said Mike Eruzione, the hockey team captain, "and I don't think any of my hockey players would have." Eruzione, reached at his home in Winthrop, Mass., said he doubted many of the hockey players would have signed any written petition, in spite of their desire to see the summer athletes compete. "Most of the guys don't want a boycott, but if that's what the government wants, they're in favor of it."

Carter said yesterday that he planned to meet with a contingent of summer Olympic athletes "to talk to them about an alternative world class competition, one that will not affect the future of the Olympic Games themselves."

Last night, before a cheering audience of Greek-Americans, Carter reiterated his support of establishing a permanent site for the summer Olympics in Greece. Holding the Games in Moscow, he said, "would violate those very principles of peace, of brotherhood and of the nonpolitical alignment of those participating in the Games -- exactly the kind of defect that would be corrected with a permanent site."

"I feel sorry for the people training for the Summer Games," said David Santee, a figure skater. "But I'm probably better off if I don't comment on the boycott."