Moscow/Sochi  - Presidents Vladimir Putin and George W Bush failed to bury their differences on US missile defence plans on Sunday but inked a "strategic framework" to guide future US-Russian relations.

A response from Russia on missile defence had been much anticipated, in view of US concessions in recent rounds security talks and Bush's success in winning NATO's backing for the project this week.

Putin's opening remarks after meeting with Bush cut to the chase: "Our fundamental attitudes to the American plan have not changed."

"I will not conceal that one of the most difficult issues was and remains missile defence in Europe," he added.

Moscow views the planned missile shield to be based in Poland and the Czech Republic as a menace to its nuclear security, while the US says will protect Europe against ballistic missile threats from "rogue" states such as Iran.

"We have a lot more work to do to convince our allies that the system is not aimed at Russia," Bush acknowledged to journalists after his one and half hour talks with the Russian president.

The two leaders have underscored warm personal ties in deflecting from a growing roster of tense security disputes during their seven- year relationship.

Putin moderated his hard line on missile defence expressing appreciation that, "The American side has heard our concerns."

He praised Bush for his "honesty, openness and willingness to listen to his partners."

And in a softer moment at the press conference, Bush said he was "a little bit nostalgic" over his final tete-a-tete meeting with the Kremlin leader. Putin leaves office in May and Bush is retiring in January.

"It proves that life moves on," added Bush.

The Sochi summit provided for Bush to hold his first in-depth talks with Putin's successor Dmitry Medvedev, highlighting both sides' attention to managing relations during the transition period.

Asked for his assement, Bush termed his meeting as "positive," describing Medvedev with characteristic bluntness as a "smart" and "straightforward fellow."

He curtly told reporters: "You can write down, 'I was impressed.'"

But the post-summit news conference stood in marked contrast to the characteristic camaraderie displayed by the two leaders in opening remarks, when Bush joked over having joined in local dancing at dinner in Putin's Black Sea residence in the resort town of Sochi.

"I am just happy that my press corps didn't see me try to dance," Bush had laughed, while news agency Interfax quoted Putin riposting, "We have been able to see you're a brilliant dancer."

True to Bush's morning promise that "When all is said and done, we'll shake hands," the US and Russian presidents announced the signing of a "strategic framework" agreement, commemorating their personal ties in a "roadmap" for the next presidents.

But the document failed to paper over entrenched differences on security and a wide range of other issues, instead incorporating them in the text.

The join statement states baldly, "The Russian side has made clear that it does not agree with the decision to establish sites in Poland and the Czech Republic and reiterated its proposed alternative."

Officials on both sides said that differences over NATO's eastward expansion, Kosovo and arms treaties were among other hot-button topics addressed in talks.

Of the legacy agreement, Putin admitted, "Of course, it does not give breakthrough solutions to existing problems."

"But it is important that the document sums up all positive things that were made over the past years whether in the spheres of security, non-proliferation, ... the struggle against terrorism," Putin said.

Bush notoriously said he had gotten a sense of Putin's soul at their first meeting, and the effort to summarize on Sunday their seven-year relationship seems an effort to bequest a written structure to their successors.

Medvedev has promised to follow Putin's lead, but while Bush has said he kept his criticism of Putin on "different matters related to democracy" under the public radar, the US presidential contenders are more critical of the Russian administration. (dpa)