The Belarusian regime on Friday backed out of a deal with the US to divest itself of all weapons-grade uranium and plutonium reserves in retaliation for economic sanctions imposed by Washington, according to dpa. Belarus will not divest itself of stocks of enriched nuclear materials as announced jointly by President Aleksandr Lukashenko and US Secretary of State Hillary Clinton after December 2010 meetings in AstanaKazakhstan, an official Minsk statement said. The former Soviet republic renounced the use of nuclear weapons in 1994 but according to international estimates retains an estimated 200 kilogrammes of materials suitable for assembling several atomic devices. Minsk was "freezing" its participation in the US-brokered agreement to rid itself of those materials because Washington had invoked new trade sanctions against Belarus which were "unfounded ... and illegal," a Belarus Foreign Ministry statement said. The US State Department on August 11 announced new sanctions against Belarus which blocked the operation of four state-owned Belarusian companies in the US, and recommended them for targeted sanctions by other countries. "The intent to levy additional sanctions was ... to respond to the continued incarceration of (Belarusian) political prisoners and crackdown on political activists, journalists and civil society representatives," a State Department statement said. "Belarus will as it has in the past provide physical security to these nuclear materials in full accordance with international standards," said Andrei Savnik, Belarusian Foreign Ministry spokesman, to Interfax. Belarus in addition was cancelling an MBA graduate study programme planned at a Minsk University under US auspices, and "other retaliatory steps are not ruled out," Savnik said. The US State Department following an initiative by President Barack Obama is pushing to bring all world stocks of enriched radioactive materials - the key element of a nuclear weapon - under international control by 2014. Belarusian President Lukashenko has long been criticised by Washington for the country's repressive regime. Lukashenko has said he believes Washington intends a regime change in Belarus. He has held near-dictatorial powers since 1996.