WASHINGTON (AP) The United States and the Czech Republic failed on Wednesday to complete an agreement on basing a U.S. anti-missile radar facility near Prague because of a Czech demand for strict environmental rules. Both sides predicted the dispute could be settled quickly.

"These aren't easy agreements to put in place," Bush said after Oval Office talks with Czech Prime Minister Mirek Topolanek. "But we feel optimistic that we will get this done."

The U.S. missile-defense system calls for an early warning radar facility in the Czech Republic combined with 10 missile interceptors in silos in Poland. It has proved controversial in Europe and further strained U.S.-Russian relations.

Moscow says that U.S. military installations so near Russian borders would threaten its security and represent an American encirclement of its former enemy. Reviving Cold War-style talk, Russia threatens to aim its own missiles at any facilities.

Bush reiterated Wednesday that Russia, with its huge missile stockpile and capabilities that could overwhelm the kind of system being planned, is not the target. Instead, the system is intended as a defense against the possibility Iran could fire long-range missiles or use them as political blackmail. Tehran has no such missiles now.

"This is a system to deal with threats that will be evolving in the 21st century," the president said. "The interesting opportunity is for Russia to realize the benefits of such a system by extending the radar coverage into their country because they will be under the same threat of radicalism that we will be 'we' collectively."

Russia's ire, however, has not cooled despite Bush's repeated assertions for more than a year since discussions began with the two Eastern European countries. Moscow has said the only way it will accept a new system is for Russia host it. That idea has little currency in Washington.

Bush seemed to signal to Moscow that the issue is not Russia's to decide. He made a point of telling reporters after his meeting with Topolanek that the Czech leader said to him privately that it is his government, not the Kremlin, that will determine what happens on Czech soil.

"He made it clear to me that the Czech Republic will be making decisions about who gets to come into their country," Bush said.

The Czechs generally have been receptive to the idea of the U.S. installing missile-tracking radar southwest of Prague. There is deeper anxiety in Poland, though, and Warsaw has become even more reticent since a new government took office in November.

Topolanek has said his government will not finish a deal with the U.S. until Poland also is on board. Still, there had been some expectations Bush and Topolanek would sign an agreement on the radar facility during their White House meetings.

At Bush's side, Topolanek said "there are only three words remaining to be resolved and discussed." Bush refused to describe them, but the Czech leader later said they deal with environmental protection standards for the radar facility.

"We're actually looking for the standards which would be the strictest possible standards to be applied in terms of ensuring and guaranteeing environmental protection," Topolanek said. "But that's just a technical matter which is going to be resolved very soon. It's not any problem."

White House press secretary Dana Perino would not say whether the U.S. opposes the level of environmental protection that the Czechs are requesting. "Obviously we are going to adhere to environmental standards wherever we go and whatever activities we are doing, both here in the United States and around the world," she said.

Any deal Topolanek signed would have to be ratified by the Czech parliament.

Bush said the negotiations amount to devising an agreement to govern how U.S. military personnel conduct themselves in the Czech Republic and under what terms. "These are all very legitimate questions that the prime minister is asking, and the same questions are being asked in Poland," he said.

As they spoke, Defense Minister Bogdan Klich said in Poland that he is freshly optimistic about talks going on there this week with the U.S. on the system.

Worried about Russia's threats of an attack, Warsaw wants U.S. help in modernizing its armed forces, such as supplying advanced missile systems or renovations to the base where the interceptors would be located. Klich said U.S. representatives have now agreed to parallel negotiations on that issue and to detail what sort of upgrades Washington will pay for and when.

Polish Prime Minister Donald Tusk, who meets with Bush at the White House next month, said that his government wants to "obtain from the Americans conditions that will allow me to say with a clear conscience, after the possible installation of the system in Poland, that Poland is more secure, not less secure."

Bush said trimming the Polish part of the plan and proceeding with just the Czech radar facility is not an option.

But he said resolution of the remaining differences with the Czechs is not far off.

"Three words is close. We started off with a blank page, and now we're down to three words," Bush said.

Copyright 2008 The Associated Press.