WASHINGTON -- As they wrapped up their two-day summit, President Clinton announced yesterday that he and Russian President Boris N. Yeltsin had agreed to accelerate the timetable for dismantling long-range nuclear missiles.

"We will make the world safer for all of us," Mr. Clinton said at a joint news conference with the Russian president.

Earlier in the day, at the Library of Congress, Mr. Yeltsin stressed the same theme in his own, typically unequivocal words.

"There are people in my country, though few, who say that our relationship with the United States is transient and that an era of confrontation will return," he said. "But I would like to tell you that we've never fought the United States, and I believe I can say as president of Russia that we will never fight the United States in the future."

Under the terms of START II, a treaty signed by Russia and the United States in 1992, each side must reduce its stockpile to between 3,000 to 3,500 intercontinental warheads by 2003.

The two presidents stressed that instead of taking the full nine years allotted to them under the treaty, each nation will start scrapping the warheads immediately.

"In other words, we save at least seven, maybe more years by doing it right away," Mr. Yeltsin said. "And we give mankind hope that our generation will be for sure living in peace."

Still, the awesome destructive power of the remaining missiles presented a somber reminder of the stakes involved in the Russian-U.S. relationship -- and of why Mr. Clinton has put so much emphasis during his administration on his dealings with Mr. Yeltsin.

"That's why we still call 'em summits," said one senior administration official.

This summit, which wrapped up last night at the Russian Embassy, where Mr. Yeltsin held a dinner for the president, was characterized by warm toasts, by several public hugs between the two men and by repeated expressions of good will between the Russian and American people.

From official accounts, it appeared that both sides negotiated resolutely in private but took pains to gloss over their differences in public.

Asked, for instance, if he had acceded to U.S. demands that Russia stop selling arms to Iran, Mr. Yeltsin replied, in essence, that he had -- but only after a current agreement between Iran and Russia expires.

"The old contract, which had been signed years ago, back in 1988, will be honored. But no other new contracts, no other new supplies, no other new shipments of weapons . . . will be shipped," Mr. Yeltsin said at the joint news conference at the White House.

However, U.S. officials said that there is still much to be resolved in this area. Mr. Clinton differed with Mr. Yeltsin's assurances but did so diplomatically.

The two nations have reached a "conceptual agreement in principle," Mr. Clinton said.

"We've made progress on the difficult issue of Russian arms sales to Iran," he added. "We've agreed to continue to work on this problem in the near future."

On the conflict in Bosnia, the two men essentially agreed to disagree.

But once again, they took pains to minimize the rift.

Congress has instructed Mr. Clinton to press the United Nations Security Council to lift the arms embargo on the nations of the former Yugoslavia in order to allow the outgunned Bosnian government forces to meet the Bosnian Serb rebels on more even terms.

Mr. Clinton also wants the embargo lifted, but the Russians didn't budge in their opposition: They insist that sending more weapons into the unstable world of ethnic Balkan politics would widen the war.

The Bosnian Muslims agreed to a Clinton administration request that they defer this issue until next spring. Asked whether, at that time, Russia would use its veto to block the issue in the Security Council, Mr. Yeltsin sidestepped the question. "In six months, we'll take a look and see," he said.

Mr. Clinton also played down the potential for conflict.

"We still have a potential difference on this issue," he said. "But the remarkable thing is how closely we have worked together on Bosnia."

A third thorny issue is Russia's insertion of troops into the civil wars raging in some of the former Soviet republics. Mr. Yeltsin pointedly refused to compare this situation to that of the U.S. intervention in Haiti -- even when invited to do so.

Asked if the United States was guilty of hypocrisy, Mr. Yeltsin scowled and said, "Nyet."

Reciprocating, Mr. Clinton volunteered that Mr. Yeltsin had declared in the talks his respect for the independence and sovereignty of the former Soviet republics. "I think Russia plainly does have a significant interest in what happens on its border," Mr. Clinton said.

This concession is not the kind that will endear Mr. Clinton to hard-line conservatives in the United States who still mistrust Russia. But it was indicative of a two-day performance by the president that showed him to be more confident on foreign policy than he had been in the past.

The news conference, however, was dominated by Mr. Yeltsin's booming voice and good humor. Using an extemporaneous style of narrative during his opening statement, Mr. Yeltsin ticked off, rapid-fire, all the issues that he and Mr. Clinton had discussed.

Noticing that the translator and the reporters were struggling to keep up with a recitation that included the phrases "nonproliferation" and "harmonizing," Mr. Yeltsin stopped suddenly.

"You can't think fast enough?" he said as the East Room rocked with laughter. "OK, then I'll go a little slower: NON-PRO-LIF-ER-A-TION of weapons. HAR-MON-IZ-ING military doctrines -- harmonizing!"

The amendment may remain, but the days when the United States wanted to squeeze Russia financially are gone. While at the White House yesterday, Mr. Yeltsin and his delegation met with a group of corporate chief executives and signed agreements on some $1 billion in U.S. investments in Russia.

However, it was Mr. Yeltsin's wife, Naina, who expressed the desires of the Russian people most simply while taking a tour of Washington with Hillary Rodham Clinton.

Visiting the Kennedy Center, she pronounced the famed arts center "magnificent and unique" and said it bespoke the United States' great wealth. But it was at Georgetown University Hospital that she became animated.

At Georgetown University Hospital, the first ladies visited with children in the pediatric playroom. Then Mrs. Yeltsin was escorted to the intensive-care unit where she seemed astonished at the sight of a 19-year-old patient with lung and kidney disease who was being treated with a high-tech life support system called ECMO.

She asked how much it cost and was told "a few thousand dollars." Then Dr. Gabriel Hauser explained that the far greater cost was the teams of doctors, nurses and therapists who must monitor the patient.

"We have everything else," she said. "But this machine is what we need."