Crawford, Texas ? President Bush warned Russia on Saturday against trying to pry loose two separatist regions in Georgia and said Moscow must end military operations in the West-leaning democracy that once was part of the Soviet empire.

Bush told reporters at his Texas ranch that Russian President Dmitry Medvedev’s signing of a cease-fire plan with Georgia was “a hopeful step.” But Russia’s vision of Georgia without the provinces of South Ossetia and Abkhazia was a nonstarter, the president said.

“These regions are a part of Georgia and the international community has repeatedly made clear that they will remain so,” said Bush, Secretary of State Condoleezza Rice at his side. “There’s no room for debate on this matter.”

The long-simmering dispute over those breakaway areas turned to war this month after Georgia launched a massive barrage to try to take control of South Ossetia. The Russian army quickly overwhelmed the Georgian forces and drove deep into its neighbor.

Russia’s attack has caused serious strains in relations with the West and heightened fears in the young democracies of Eastern Europe.

Bush discussed the situation for nearly an hour with Rice, who arrived at the ranch around 5:30 a.m. local time from a quick trip to Georgia. They were joined via secured videoconference from Washington by other members of Bush’s national security team, including Vice President Dick Cheney, Defense Secretary Robert Gates and national security adviser Stephen Hadley. Bush also spoke to Georgian President Mikhail Saakshvili, reiterating U.S. support.

The Russian foreign minister, Sergey Lavrov, said this past week that Georgia could “forget about” getting back South Ossetia and Abkhazia, which sympathize with Moscow. Medvedev recently met at the Kremlin with leaders from those regions, raising the prospect Russia could absorb them.

Bush countered that Georgia’s borders need to be respected. He said the U.N. Security Council had passed numerous resolutions based on the premise that South Ossetia and Abkhazia remain within Georgia and that international negotiations seek to resolve conflicts in those areas. “Russia itself has endorsed these resolutions,” Bush said.

The chilling of relations between Washington and Moscow comes as the U.S. is sealing the deal on a missile shield in Europe – an issue already unraveling ties between the two former Cold War foes. Poland and the U.S. signed an agreement Thursday for Poland to accept a missile interceptor base as part of a system the U.S. says is aimed at blocking attacks by adversaries such as Iran. The missile deal awaits approval by Poland’s parliament and signing by Rice during a future visit to Warsaw, possibly in the week ahead.

Moscow feels the system is aimed at Russia’s missile force. A Russian general was quoted by Interfax News Agency on Friday as saying that by deploying the system, Poland is “exposing itself to a strike – 100 percent.”