Russia's Defence Minister Sergei Shoigu and his Belarusian counterpart Viktor Khrenin have signed an agreement to deploy Russian tactical nuclear weapons in Belarusian territory.

Russia's Defence Ministry announced on Thursday that the two defense chiefs signed the document in the Belarusian capital Minsk.

Shoigu reportedly said Russia has no choice but to take a countermeasure amid rapid growth of tensions on the two countries' borders.

He said Russia will proceed with the deployment following a decision by its chief commander.

He also said Russia is not transferring its nuclear weapons to Belarus, and will continue to decide on their management and use.

Shoigu added that the weapons are kept in a special storage facility in Belarus. He stressed that the two countries abide by international legal obligations.

The move comes after Russian President Vladimir Putin announced in March that Russian tactical nuclear weapons would be deployed in Belarus.

Putin also said Russia planned to finish building a storage facility for the weapons in Belarus by July 1.

The deployment is widely viewed as a warning from the Kremlin to Western nations that are boosting their military support for Ukraine.