STOCKHOLM, JUNE 8 -- Hours after she broke her silence on the Iran-contra arms sale scandal to say she does not think it will ruin her husband's presidency, Nancy Reagan was greeted here today by demonstrators protesting U.S. policy in Central America and chanting "Nancy go home" before she was cheered at an antidrug concert.

An estimated 200 protesters, held back about 100 yards by police with dogs as Mrs. Reagan arrived at a local high school for the afternoon concert, carried signs saying "Hands Out of Central America" and "Nancy, Your Luxury Is the Blood of Other People." The first lady did not react.

Later today, police in helmets and plastic riot shields arrested about 90 of 150 protesters who gathered outside Mrs. Reagan's hotel after they threw smoke canisters, blue paint, toilet paper and eggs as they shouted "Drugs kill fewer than the Reagan regime" and "Crush U.S. imperialism."

"We have 90 people detained on suspicion of rioting and causing damage," police spokesman Curt Nilsson told reporters. "This is unprecedented."

Inside the Grand Hotel, Mrs. Reagan was getting ready for dinner aboard a boat cruising the Stockholm Archipelago as guest of Sweden's Minister of Health Gertrud Sigurdsen.

Her remarks about the Iran-contra arms sales -- her first since congressional hearings on them began in May -- were made in response to questions in an impromptu press conference aboard Executive One, the presidential backup plane, on her way here to visit anti-drug-abuse programs for three days.

"Certainly it's too bad it happened," she said. "You hate to have people out there doing things you don't know about."

She refused to be drawn into any comprehensive or substantive discussion of the controversy, commenting only that "it looks that way" when a reporter noted that Lt. Col. Oliver North seemed to be involved with considerable sums of money that changed hands.

She said both she and Reagan feel "exactly the same" about the Iran-contra situation, but said "I'm not going to tell you" what that feeling is.

She said she has seen "some" of the televised live coverage of the hearings, "if I'm getting dressed or undressed," but that "I have other things to do -- I read about it in the papers. I see it in the nightly news."

Asked if she thought the Iran-contra problem might be merely a footnote to the Reagan presidency, she said, with a laugh, "I don't know how you want to word it."

The only time she seemed impatient with her questioners came after someone asked about the Reagan legacy and whether she thought it would be an arms agreement with the Soviets.

"I thought we were going to talk about drug abuse in Sweden," she scolded, mildly. Then, with a little laugh, she went on to say, "Oh, gosh, there's so much I think he's done, and it's so long since we've had an eight-year presidency. I just think he's done so much. Wait until the eight years is over and then ask me."

Before the antidrug concert at Vilunda High School, she visited a communal political action program where community leaders explained a system they adopted in 1982 to detect and treat young abusers.

She got two standing ovations from the audience of about 500 young people at the concert, which was organized by a group known as Swedish Entertainers Against Drugs. She was introduced by popular Swedish entertainer Lars Berghagen, who said she "could be sitting by the Riviera drinking champagne, but she has chosen to join us ... to say three words, 'Just Say No.' " She danced with him briefly on stage after he sang her a song in Swedish.

During the flight here from Venice, where Reagan is attending the seven-nation economic summit, Mrs. Reagan also answered a range of other questions, including some about the Reagans' so-called second honeymoon in Venice and whether the media overreacted to her role in ousting former White House chief of staff Donald Regan.

She seemed both amused and amazed at stories that have been appearing in the Italian press about the second honeymoon at Villa Condulmer, where the Reagans relaxed for four days last week.

"The things that I was supposed to have done in that villa were quite extraordinary -- a Jacuzzi, a beauty parlor, a bathroom, horses and Venetian bed linens," she said. "There were so many things I've forgotten but it made interesting reading even if I didn't do any of them."

Of her influence on Reagan, she reiterated her explanation as given to the American Newspaper Publishers Association in New York this spring.

"I think it was silly to think after being married for 35 years you don't have your own opinions and you don't voice your own opinions to your husband," she said. "Sometimes he agrees, sometimes he doesn't agree. Just being wife of a president doesn't mean you can't say what you think."

Asked about her role in getting rid of Regan and whether the press had blown it out of proportion, she raised her eyebrows in mock shock.

"I thought a couple of columnists were extreme," she said.

And of a possible U.S.-Soviet summit this fall in the United States, she said that she thought it would be nice if there were one. She said she did not know, however, if she and the president would entertain Soviet leader Mikhail Gorbachev and his wife Raisa at the Reagans' California ranch.

"It depends on how it all works out," she said.

She usually greets reporters traveling with her aboard Executive One on her foreign trips, and this time she also snapped some of their pictures with the camera given her last month by the White House News Photographers Association.

After she commented on how easy the Olympus camera was to use, she was reminded it was made in Japan.

"You had to spoil the whole thing," she joked. "I won't take your picture."