Belarusian air force crews have completed their training for using tactical nuclear weapons as part of Russia’s plan to deploy the weapons to its ally Belarus amid the fighting in neighboring Ukraine, the Russian Defense Ministry said Friday.

The ministry released a video in which a Belarusian pilot said that the training course in Russia had given the crews of the Belarusian air force’s Su-25 ground attack jets the necessary skills for using the weapons.

Russian President Vladimir Putin declared last month that Moscow planned to put some of its tactical nuclear weapons in Belarus. It was another attempt by the Kremlin leader to dangle the nuclear threat to discourage the West from supporting Ukraine.

Russia has a union agreement with Belarus that envisions close political, economic and military ties. Russian troops used Belarusian territory to roll into Ukraine from the north in February 2022 and have maintained a presence in Belarus.

The deployment of Russian tactical nuclear weapons to Belarus would put them closer to potential targets in Ukraine and NATO members in Eastern and Central Europe. Belarus shares a 778-mile border with NATO members Latvia, Lithuania and Poland.

Such weapons are intended to destroy enemy troops on the battlefield. They have a relatively short range and much less power compared with nuclear warheads fitted to long-range strategic missiles, which are capable of obliterating whole cities.

Putin said that construction of storage facilities for tactical nuclear weapons would be completed in Belarus by July 1. Russia also has helped modernize Belarusian warplanes to adapt them to carrying nuclear weapons and provided the country with Iskander short-range missiles that could be fitted with a nuclear warhead.

Putin has emphasized that Russia would retain control over any nuclear weapons deployed to Belarus, just as the U.S. controls its tactical nuclear weapons on the territory of its NATO allies.

The authoritarian president of Belarus, Alexander Lukashenko, has suggested that some of Russia’s strategic nuclear weapons might also be deployed to Belarus along with part of Moscow’s tactical nuclear arsenal.

Belarusian Defense Minister Viktor Khrenin again mentioned the possibility Friday, saying “it could be the next step,” if the West continued what he described as its hostile course.

“We will respond to force only with force. Otherwise, they don’t get it in the West,” Khrenin said. “We are already preparing the sites that we have.”

Belarus, Kazakhstan and Ukraine had Soviet nuclear weapons stationed in their territory but handed them over to Russia after the 1991 collapse of the Soviet Union.