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

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

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

During the interview, Putin also said Russia has helped Belarus convert 10 aircraft to make them capable of carrying tactical nuclear warheads. Russia will start training pilots to fly the re-configured planes early next month, he added.

Key context: The government in Belarus, which is situated west of Russia on Ukraine’s long northern border, is among Moscow’s closest allies.

Belarus has had no nuclear weapons on its territory since the early 1990s. Shortly after gaining independence following the collapse of the Soviet Union, it agreed to transfer all Soviet-era weapons of mass destruction stationed there to Russia.

Belarus helped Russia launch its initial invasion of Ukraine in February 2022, allowing the Kremlin’s troops to enter the country from the north. There have been fears throughout the conflict that Belarus will again be used as a launching ground for an offensive, or that Minsk’s own troops will join the conflict.

Global tensions: Even though there is no guarantee the Russian leader will follow through with his plan to station the weapons in Belarus, any nuclear signaling by Putin will cause concern in the West.

Since invading Ukraine more than a year ago, the Russian leader has used escalating rhetoric on a number of occasions, warning of the “increasing” threat of nuclear war and suggesting Moscow may abandon its “no first use” policy.

The United States has sought to make it clear to Putin the consequences of any use of nuclear weapons in Ukraine, even low-yield tactical devices.

Speaking in October, 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 nuclear use by Russia.

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

“The mistakes get made, the miscalculation could occur, no one could be sure what would happen and it could end in Armageddon,” he said.

CNN’s Peter Wilkinson, Frederik Pletigen, Zahra Ullah, Claudia Otto and Rob Picheta contributed.