Russian Deputy Foreign Minister Oleksandr Hrusko said the accelerated deployment of upgraded US B61 tactical nuclear weapons at NATO bases in Europe would lower the “nuclear threshold” and that Russia would take the move into account in its military planning, Reuters reported.

Russia’s invasion of Ukraine sparked the worst confrontation between Moscow and the West since the 1962 Cuban Missile Crisis, when the two Cold War superpowers came closest to nuclear war.

Russia has about 2,000 operational tactical nuclear warheads, while the US has about 200 such units, half of which are based in Italy, Germany, Turkey, Belgium and the Netherlands.

Politico reported that the United States said in a closed NATO meeting that it would accelerate the deployment of an upgraded version of the B61, the B61-12, with the new weapon expected to arrive at European bases in December, several months earlier than planned.

“We cannot ignore plans to modernize nuclear weapons, those free-falling bombs that are in Europe,” Russian Deputy Foreign Minister Oleksandr Hrusko told the state news agency RIA.

According to a study by the Federation of American Scientists, the B61-12 gravity bomb has a smaller nuclear warhead than many previous versions, but is more accurate and can penetrate underground.

“The United States is modernizing them, increasing accuracy and reducing the power of the nuclear charge, that is, turning these weapons into ‘combat weapons,’ thus lowering the nuclear threshold,” Deputy Lavrova said.