Russia and Belarus are coordinating activities involving nuclear arms, apparently to step up pressure on the United States and its European allies.
Russia's defense ministry announced on Monday that preparations have begun for military drills by its tactical nuclear weapons units, at the instruction of President Vladimir Putin.
In Belarus, Defence Minister Viktor Khrenin revealed on Tuesday that President Alexander Lukashenko had ordered an inspection of the country's nuclear weapons units.
The Putin administration has been deploying tactical nuclear weapons in Belarus.
A senior Belarusian national security official explained that the inspection is being synchronized with drills by the Russian forces.
Belarus' state-run news agency reports that Lukashenko claimed in a speech on Tuesday that the tactical nuclear weapons deployed in his country are for deterrence purposes. He also accused Western nations of carrying out military provocations.
The news agency also says Lukashenko will meet Putin in Moscow on Wednesday and discuss future drills.