Moscow - Vladimir Putin and George W Bush sealed their seven-year presidential relationship with a final "straight" tete-a- tete Sunday, joking and acting out their self-acclaimed camaraderie.

But "straight" was the sole compliment left after relations became strained by a host of recent disagreements that left them papering over the cracks.

"I've come to respect you. You've been a strong leader, not afraid to tell me what's on your mind," Bush began.

"I've always valued (Bush's) high human qualities, his honesty, openness, willingness to listen," Putin rejoined.

Neither did Bush leave off compliments in first in-depth talks with Putin's successor, Dmitry Medvedev telling reporters curtly: "You can write down: 'I was impressed'."

The two were forced on the defensive when reporters prodded them over the fraught US-Russian stances on missile defence, NATO's enlargement eastward, and expiring Cold War-era arms treaties.

"The meeting was called to minimize the damage that has occurred in recent months," said Kremlin-linked analyst Vladimir Nikonov, who heads the Politika Foundation.

Putin admonished the press corps over "beliefs based on stereotypes", while Bush resorted to his mantras that "the Cold War is over" and "Russia is not the enemy."

But on Sunday, US plans to build a missile defence shield - an idea dating to the 1980s - remained a no-go proposal for Russia, despite high expectations of detente in view of recent US concessions and Bush's success in winning NATO backing for the missile system this week.

Putin's opening remarks after meeting with Bush cut to the chase: "Our fundamental attitudes to the American plan have not changed," he said. "I will not conceal that one of the most difficult issues was and remains missile defence in Europe."

Moscow views the planned Polish- and Czech-based missile shield as a menace to its nuclear security, while Bush insists it will protect against states "that would hold us hostage" with missile threats.

"We have a lot more work to do to convince Russia," Bush admitted.

Smiles quickly reappeared when Bush and Putin traded pats on the back before the cameras and made good on Bush's morning promise that "when all's said and done, we'll shake hands."

But the concrete results of the summit, the long touted "strategic agreement" as a legacy for their successors, left analysts hard- pressed for an assessment.

The statement reads, "The Russian side has made clear that it does not agree with the US decision to establish missile sites ... while it appreciates the measures that the US has proposed," making it seem an agreement to disagree.

Of the legacy agreement, Putin said: "Of course, it does not provide breakthroughs to existing problems. But it is important that the document sums up all positive things."

Vladimir Pribylovsky, head of the Panorama think tank, said afterwards that Putin cannot compromise on missile defence, because anti-American rhetoric has been part of the Kremlin's domestic policy of reviving Russia's self-esteem.

But outwardly Putin does not want confrontation with the United States, Pribylovsky and other analysts were saying Sunday.

A political scientist with the Moscow Carnegie Centre, Alexey Malashenko, said that the "sugar-coated" talks could be seen as a way to let Medvedev take a softer line toward the United States after his inauguration on May 7.

Other observers added that the written agreement could also serve the Kremlin as a way to manage relations with Washington when Bush goes in January 2009. (dpa)