Face to face for the first time, President Bush and Russian President Vladimir Putin pledged Saturday to deepen their nations' bonds and to explore the possibility of compromise on U.S. missile defense plans that Moscow has bitterly opposed.

Despite mixed signals from his Russian counterpart, Bush said, "We have a great moment during our tenures to cast aside the suspicions and doubts that used to plague our nations."

Putin showed a surprising "receptivity" to missile defense, particularly the need to conduct research that could violate the 1972 Anti-Ballistic Missile treaty, Bush said.

"Nothing was rejected out of hand," Bush told The Associated Press as he closed his first overseas trip and returned to Washington on Saturday night.

Putin himself hinted at the possibility of a "very constructive development" on the ABM issue. "I think we can work out a common approach," he said.

Still, he warned Bush that any effort to go it alone can only make U.S.-Russian relations "more complicated." Putin coldly declined to restate Russia's opposition: "The official position of the Russian government is known."

Emerging from more than two hours of inaugural talks at Brdo Castle, Bush stressed the positive by announcing that Putin will visit Bush's Texas ranch for an autumn summit. Bush, in turn, will visit Putin at his home in Russia.

Senior officials on both sides were ordered to begin talks, including military-to-military negotiations, designed to bridge differences on issues ranging from missile defense to NATO expansion - both opposed by Moscow.

"The differences in approaches do exist, and naturally in one short moment, it's impossible to overcome all of them," Putin said.

Both sides said no specific breakthroughs were reached, and none were expected in the short term.

The summit brought together two men - one a former KGB agent, the other the son of a former CIA chief - whose sprawling nations stood for years on the brink of nuclear destruction. They, as well as their nations, are adjusting to the shifting dynamics of the post-Cold War world.

"Can I trust him?" Bush said. "I can. And from that basis, we can begin a very fruitful relationship." He called Putin a family man, a patriot. "I was able to get a sense of his soul,aBush told reporters.

Such an unimpeachable endorsement caught Bush's advisers by surprise and some worried he may regret his words if Putin strays from democratic reforms.

Bush saluted his Russian counterpart as "an honest, straightforward man who loves his country."

Bush met Putin at the elegant 16th-century estate that was a favorite Alpine resort for the late Yugoslav dictator Josip Broz Tito. Sweeping green fields and a craggy mountain top formed the backdrop as Bush tried to put his signature charm to work.

"I was so impressed that (Putin) was able to simplify his tax code in Russia with a flat tax. I'm not so sure I'll have the same success with Congress," he joked.

Bush hoped to thaw the chill in U.S.-Russian relations over his plan to scrap the 1972 Anti-Ballistic Missile Treaty and pursue missile defense. Bush argues that the offensive capabilities of "rogue" nations such as Iran and Iraq gravely threaten the U.S. and its allies.

Putin called the ABM treaty the "cornerstone of the modern architecture of international security," and added: "Any unilateral actions can only make more complicated various problems and issues."

In the brief interview, Bush told AP, "We talked straightforward. Nothing was rejected out of hand."

Asked if that included missile defense, Bush repeated, "Nothing was rejected out of hand, and there was a receptivity that I was most pleased to see. ... It became clear to me in our discussion that the Russians feel the same threats we feel."

At the news conference, Bush said he did not offer incentives to Putin to gain Russian acquiescence.

White House aides had said in advance that Bush hopes to eventually offer Putin inducements such as arms purchases, military aid and joint anti-missile exercises with Russia. But first, advisers must hammer out the details.

Bush asked Secretary of State Colin Powell and Defense Secretary Donald Rumsfeld to work with their Russian counterparts on a "new approach for a new era" in security arrangements. And Treasury Secretary Paul O'Neill and Commerce Secretary Don Evans will head to Moscow soon to work on economic and commercial ties.

Bush and Putin meet again next month in Italy at the G-8 summit of industrial powers.

Asked if Putin seemed open to U.S. research on missile defense, Bush said, "That's obviously the intent of the discussions."

A more muted Putin said the United States and Russia must work together to identify security threats and officials from both countries should sit down to "try to find a way together to solve these problems."

Bush's National Security Adviser Condoleezza Rice welcomed that as an invitation to further dialogue.

On another contentious issue, Bush reiterated his support for expanding NATO while Putin went to lengths to explain his apprehension about the Western alliance expanding toward Russia's borders.

Drawing chuckles from Bush, Putin fished around on his lectern for a declassified 1954 memo in which NATO, casting the Soviet Union as an enemy, rejected Soviet interest in membership.

"There is no need to fire up this whole situation," Putin said.