Moscow has accused the US of breaking a disarmament agreement between the two countries, the Russian foreign ministry said Saturday, according to local news agency reports, dpa reported.

President Dmitry Medvedev and his US counterpart Barack Obama signed the most wide-ranging nuclear arms control treaty for decades in Prague in April, and Russian-US relations seemed to have improved.

The infringement of which Russia is now accusing the US concerns the April agreement’s predecessor, START-1, which expired December 1, 2009.

The US had reequipped, in contravention of the agreement, five silos previously used for intercontinental ballistic missiles at the Vandenburg air base with interceptor missiles, the ministry alleged.

The reequipping of US bombers was also a cause for concern.

“The US has not yet provided any convincing proof that remodelled bombers could not be rearmed with nuclear weapons,” the foreign ministry said.

Washington had also violated terms of the agreement on biological and chemical weapons.