Belarus has suspended an effort to fully give up its Soviet-era stockpile of highly enriched uranium with U.S. assistance in response to new American sanctions, the government said Friday.
Belarus will make sure the material is stored securely in line with its international commitments, the Foreign Ministry said.
The U.S. has conducted a longtime effort to secure nuclear materials in former Soviet nations to prevent them from falling into the wrong hands.
"We are disappointed with Belarus' announcement," U.S. State Department spokeswoman Heide Bronke Fulton said in Washington. "We hope that Belarus intends to meet its stated objective of the elimination of all of its stocks of highly enriched uranium. This is a responsible contribution to global security."
Last December, Belarus committed to eliminating its stockpile of highly enriched uranium by year's end. Prior to the agreement, Belarus, Russia, the U.S., and the International Atomic Energy Agency moved two shipments of the material into secure facilities in Russia.
President Alexander Lukashenko says Belarus still has "hundreds of kilograms" of highly enriched uranium, but his government has refused to disclose the exact amount.
Foreign Ministry spokesman Andrei Savinykh said the decision to freeze the stockpile's elimination was made because of "unfounded and illegitimate U.S. sanctions."
The U.S. and the European Union introduced new sanctions against Lukashenko's government for its crackdown on the political opposition.
Belarus' former leader Stanislav Shushkevich told The Associated Press that Friday's announcement appeared to be an attempt by Lukashenko to blackmail the West.
"The Belarusian authorities are trying to scare the U.S.," he said.
Bronke Fulton said "respect for democracy and human rights remains central to improving relations with Belarus. The continuing crackdown and incarceration of political prisoners led the United States to impose additional sanctions this month.
"Our policy remains a firm call for the immediate and unconditional release of all political prisoners," she said.
Belarus, Ukraine and Kazakhstan shipped all of their Soviet-era nuclear weapons to Russia in the early 1990s, but have retained stockpiles of nuclear materials.
Matthew Lee in Washington contributed to this report.