Strongman Alexander Lukashenko, who has been in power in Belarus for almost 30 years, is a key Putin ally.
Back in February 2022, Minsk allowed the Kremlin to launch its invasion of Ukraine from Belarusian territory.
Fears have since risen that Belarus may join its ally’s offensive, but Lukashenko said he would do so “only if attacked”.
In an interview broadcasted Saturday, 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 Lukashenko and said “we agreed to do the same.”
Russia will start training crews on Apr 3 and plans to finish the construction of a special storage facility for tactical nuclear weapons by Jul 1.
Putin has previously said nuclear tensions were “rising” globally but that Moscow would not deploy first.
The Russian leader said renewed discussions with Lukashenko on the issue were spurred by a British official’s suggestion to send depleted uranium weapons to Ukraine.
Russia will respond if the West supplied Ukraine with such ammunition, he added.
“Russia of course has what it needs to answer. Without exaggeration, we have hundreds of thousands of such shells. We have not used them yet.”
He said the weapons “can be classified as the most harmful and hazardous for humans … and also for the environment”.
Depleted uranium munitions are highly effective at piercing armour plate, but their use is controversial.
The metal is toxic for the soldiers who use the weapons and for civilians in areas where they are fired.