ROSTOCK (AP) -- Vladimir Putin, bitterly opposed to a U.S. missile shield in Europe, presented President Bush with a surprise counterproposal Thursday built around a Soviet-era radar system in Azerbaijan rather than new defenses in Poland and the Czech Republic. Bush said it was an interesting suggestion and promised to consider it.

The Russian president said he would abandon his threat to retarget missiles on Europe — if Bush accepted the Kremlin's missile-defense proposal.

"This is a serious issue and we want to make sure that we all understand each other's positions very clearly," Bush said after an hour-long meeting with Putin. Speaking through a translator, Putin said he was "satisfied with the spirit of openness" from Bush.

With U.S.-Russian relations at a post-Cold War low, the two leaders sought a fresh start on the sidelines of the annual summit of industrialized nations. Tensions were raised in recent days by Bush's accusations that Putin was backsliding on democracy, and by Putin's charges that Bush was starting a new arms race with missile defenses.

At the summit, Bush and Putin joined other world leaders in a compromise on a plan to attack global warming. They agreed to seek substantial reductions in greenhouse gas emissions but stopped short of committing themselves to specific targets, apparently because of U.S. opposition.

While they tried to present a cordial picture, Bush and Putin could not even agree on their differences. Bush said Putin "is concerned that the missile defense system is not an act that a friend would do." Putin made a point of correcting Bush. "I have not said that friends do not act in this way," the Russian leader said.

Putin's counterproposal would use an aging radar installation at Gabala in northern Azerbaijan, a central Asian country bordering the Caspian Sea.

Putin told Bush he had talked about his proposal with Azerbaijan's president, Ilham Aliev, and that he was amenable to the idea, Steve Hadley, Bush's national security adviser said. Kremlin spokesman Dmitry Peskov said, "This offer shows once again that President Putin is ready to find consensus and he's ready to find solutions, not by confronting, not by threatening anyone — well, he's never done that, actually — but by working together."