Shrouded in the pre-dawn darkness, a squad of Georgian policemen accompanied by American security agents entered a nuclear research laboratory outside this capital on Thursday, loaded a cargo of bomb-quality uranium onto a specially prepared truck and drove into the night.

The cache of uranium and spent nuclear fuel arrived at a military base in Scotland early Friday aboard a U.S. transport plane, a British news agency said.The operation was one of the most secretive of several that have brought nuclear material out of the former Soviet Union. Directors of the plant said it turned Georgia into a nuclear-free zone, and Western officials hope that it set a precedent for operations that can be duplicated in other former Soviet republics.

President Eduard Shevardnadze said he was grateful to the Western powers that had agreed to remove the uranium from his country.

"The cost of taking care of this reactor, of maintaining and guarding it, was more than we could afford," Shevardnadze said in an interview. "We appealed to the United States and Britain, and they kindly accepted it."

"We did not want to provide anyone with the possibility to build an atomic bomb. Now, after what has been done, there is no such danger. Everything has come under the control of responsible experts."

About one-fourth of Georgian territory is held by separatist rebels. Western diplomats and Georgian security planners feared that agents of the separatists, or squads working for groups in nearby Iran, Iraq or Chechnya, would try to seize the uranium and use it for blackmail.

Experts said there was enough uranium here to build a device capable of contaminating a large area, or even a nuclear bomb. Asked who might have wanted to steal the uranium, Shevardnadze replied: "Please don't make me answer that question."

British Prime Minister Tony Blair was forced to defend his government's decision to accept the material on Wednesday, as Green-peace activists protested outside his official Downing Street residence.

Blair said it was essential to keep rebels in the troubled nation from seizing such material.

But environmentalists accused the government of using Scotland as a nuclear dumping ground.