The EU's foreign policy chief Josep Borrell has warned that Brussels was ready to impose new sanctions on Belarus if it will proceed with the plan to host Russian nuclear weapons.

"Belarus hosting Russian nuclear weapons would mean an irresponsible escalation and threat to European security. Belarus can still stop it, it is their choice. The EU stands ready to respond with further sanctions," Borrell posted on social media on Sunday.

Russian President Vladimir Putin announced on Saturday his country would station tactical nuclear arms in Belarus.

Putin said the deployment was similar to moves from the United States, which stores such weapons in bases across Belgium, Germany, Italy, the Netherlands and Türkiye, an analogy western allies called "misleading".

With fears of a nuclear war rising since the war in Ukraine began, experts believe that any Russian strike would likely involve small-size battlefield weapons, called "tactical" as opposed to "strategic" high-powered long-range nuclear weapons.

The Ukrainian foreign ministry accused Russia of breaching its obligations, and of undermining the "nuclear disarmament architecture and the international security system in general".

It called on "all members of the international community to convey to the criminal Putin regime the categorical unacceptability of its latest nuclear provocations," Kiev said.

"Ukraine expects effective actions to counteract the Kremlin's nuclear blackmail from the United Kingdom, China, the United States and France," it added.

"We demand that an extraordinary meeting of the UN Security Council be immediately convened for this purpose.".

In Saturday's interview, Putin said the move to deploy tactical nuclear weapons to Belarus was "nothing unusual".

"The United States has been doing this for decades. They have long placed their tactical nuclear weapons on the territory of their allies," Putin said.

Putin said he spoke to Belarusian Alexander Lukashenko and said "we agreed to do the same."

Russia will start training crews on April 3 and plans to finish the construction of a special storage facility for tactical nuclear weapons by July 1.

READ MORE:Putin says Russia will station tactical nuclear weapons in Belarus