Russia plans to deploy tactical nuclear weapons in neighboring Belarus, President Vladimir Putin told state television on Saturday.

Moscow will complete construction of a special storage facility for tactical nuclear weapons in Belarus by early July, Putin told state broadcaster Russia 1.

The Russian leader said Moscow has already deployed an Iskander short-range missile system – which can be equipped with nuclear or conventional warheads – to Belarus.

During the interview, Putin also said Russia helped Belarus convert 10 planes so they could carry tactical nuclear warheads. Russia will begin training pilots to fly the reconfigured planes early next month, he added.

Belarus has not had nuclear weapons on its territory since the early 1990s. Shortly after gaining independence after the collapse of the Soviet Union, it agreed to transfer to Russia all Soviet-era weapons of mass destruction stationed there.

Belarus aided Russia in its first invasion of Ukraine in February 2022, allowing Kremlin troops to enter the country from the north. Throughout the conflict there have been fears that Belarus will again be used as a launching pad for an offensive or that Minsk’s own troops will join the conflict.

On several occasions since invading Ukraine more than a year ago, the Russian leader has used escalating rhetoric, warning of the “increasing” threat of nuclear war and suggesting that Moscow could abandon its “No First Use” policy.

The United States has tried to explain to Putin the consequences of any use of nuclear weapons in Ukraine, even low-yield tactical devices.

In an October speech, US President Joe Biden told CNN’s Jake Tapper, “It would be irresponsible for me to talk about what we would or wouldn’t do” in response to Russia’s use of nuclear weapons.

But Biden hinted at the possibility of a rapid escalation of events.

“The mistakes are made, the miscalculation might occur, no one could be sure what was going to happen and it could end in Armageddon,” he said.