Russia and Belarus signed a deal Thursday formalizing the deployment of Moscow’s tactical nuclear weapons on the territory of its ally, although control of the weapons remains in the Kremlin.

Russia on Thursday said the step was driven by rising tensions with the West.

“In the context of an extremely sharp escalation of threats on the western borders of Russia and Belarus, a decision was made to take countermeasures in the military-nuclear sphere,” Russia’s state-owned TASS news agency quoted Russian Defence Minister Sergei Shoigu as saying.

Putin revealed the strategy for the nuclear deployment in an interview with state television on March 25, marking Moscow's first outside of Russian boundaries since the collapse of the Soviet Union in 1991.

"The collective West is essentially waging an undeclared war against our countries," Putin's defence minister, Sergei Shoigu, said at a meeting with his Belarusian counterpart in Minsk, according to Russia's defence ministry.

The West, Shoigu said, was doing all it could "to prolong and escalate the armed conflict in Ukraine."

He said the documents they were signing concerned the process for storing tactical nuclear weapons in a special facility in Belarus.

Since invading Ukraine last year, Putin has said repeatedly that Russia would be ready to use nuclear weapons if needed to defend its “territorial integrity”.

NATO said at the time it did not see any need to adjust its own nuclear posture, although the military alliance cast Putin’s nuclear rhetoric as “dangerous and irresponsible”.

The precise date of the deployment of Russian tactical nuclear weapons in Belarus, which borders three NATO members—Poland, Lithuania, and Latvia—is yet unknown. The weaponry will continue to be in Russian hands.

Strategic nuclear weapons are those that are intended to destroy the largest cities of the United States or Russia, whereas tactical nuclear weapons are those that are employed for particular tactical gains on the battlefield.

When it comes to tactical nuclear weapons, Russia has a significant numerical advantage over the United States and the NATO military alliance: the United States estimates that Russia has about 2,000 such operational tactical warheads.

Iskander-M missiles, which are capable of carrying conventional or nuclear warheads, have reportedly been given to the Belarusian military, and some Su-25 aircraft have been modified for the potential use of nuclear weapons, according to Shoigu.

"Belarusian servicemen have received the necessary training," Shoigu was quoted as saying by his ministry. He said the two countries could take further measures to ensure their security.

"NATO's military activities have become as aggressive as possible," Shoigu said.

Because of Putin's comments made during the crisis in Ukraine, the United States has claimed that the world faces the greatest nuclear threat since the 1962 Cuban Missile Crisis. Moscow, however, claims that the United States has misconstrued its position.

The Treaty on the Non-Proliferation of Nuclear Weapons, which was signed by the Soviet Union, states that no nuclear country may transfer nuclear weapons or technology to a non-nuclear power, although it does permit the deployment of nuclear weapons outside of its boundaries while still being under its control.

Image source: AP