Moscow ? Russian President Vladimir Putin warned President Bush’s top two Cabinet officials on Friday to back off U.S. missile defense plans for eastern Europe as high-level talks yielded little more than a pledge to meet again.

Despite presenting new cooperation proposals intended to bring Moscow on board, Secretary of State Condoleezza Rice and Defense Secretary Robert Gates failed in a series of tough meetings to turn around Moscow’s opposition to the system and other strategic issues.

Putin set the tone early on when he hosted Rice and Gates and their Russian counterparts at his country home outside Moscow and delivered a stern rebuff to U.S. plans to push ahead with establishing missile defense facilities in Poland and the Czech Republic.

In combative comments that took the U.S. side aback during a photo session, Putin criticized Bush’s pet project and threatened to pull out of a Cold War-era treaty that limits intermediate-range missiles.

“We may decide someday to put missile defense systems on the moon, but before we get to that we may lose a chance for agreement because of you implementing your own plans,” he told Rice and Gates in Russian, according to an Associated Press translation.

“We hope that in the process of such complex and multifaceted talks you will not be forcing forward your previous agreements with eastern European countries,” Putin said.

The United States has repeatedly rejected Russian demands to freeze U.S. negotiations with Poland and the Czech Republic and Rice did so again Friday, said three senior U.S. officials present at the sessions with Rice, Gates, Russian Foreign Minister Sergey Lavrov and Defense Minister Anatoly Serdyukov.

The officials, who spoke on condition of anonymity to describe diplomatic discussions, maintained that differences were narrowed but progress was incremental and might not produce ultimate understandings.

“I agree that we did not agree on anything today,” one official told reporters. He added quickly that neither Washington nor Moscow had expected significant breakthroughs.

Rice and Lavrov announced at a news conference after the meetings that the two sides would meet again in Washington in six months to review a “strategic framework” on evaluating and addressing the missile threat posed by rogue states, principally Iran.

The U.S. proposals are intended to ease fears that its missile defense plans threaten Russia’s nuclear deterrent and include the creation of a so-called “joint regional missile defense architecture” that would protect the United States, NATO allies in Europe and Russia.

As part of that scheme, experts from all nations covered by the system would be based at missile defense facilities to try to improve coordination and transparency.

A spokesman for Putin, Dmitry Peskov, told reporters in a conference call that “some of them are quite interesting and the Russian side will start examining this proposal.”

But, he stressed: “It will take some time before we are able to make public our estimation.”

Shortly before the talks with Putin began, Lavrov strolled into the house’s billiards room, where American reporters had gathered, for a cigarette break.

He was asked whether he expected any breakthroughs in the talks.

“Breaks, definitely. Through or down, I don’t know,” he said.