MOSCOW (AP) — Belarus' authoritarian President Alexander Lukashenko said Tuesday his country is hosting dozens of Russian nuclear weapons and will prepare facilities for the planned deployment of Moscow's newest hypersonic ballistic missile.

His remarks came after he and President Vladimir Putin signed a treaty last week that gave security guarantees to Belarus, Moscow’s closest ally, including the possible use of Russian nuclear weapons to help repel any aggression.

The pact follows Moscow's revision of its nuclear doctrine, which for the first time placed Belarus under the Russian nuclear umbrella amid the tensions with the West over the conflict in Ukraine.

“I have warned all my enemies, ‘friends’ and adversaries: If you step on the border, the answer will be momentary,” Lukashenko said.

Lukashenko, who has ruled Belarus with an iron hand for over 30 years and has relied on Kremlin subsidies and support, allowed Russia to use his country’s territory to send troops into neighboring Ukraine in 2022 and to host some of its tactical nuclear weapons.

Unlike nuclear-tipped intercontinental ballistic missiles that can destroy entire cities, tactical nuclear weapons for use against troops on the battlefield are less powerful.

Russia hasn't disclosed how many, but Lukashenko said Tuesday that his country currently has several dozen of them.

“I have brought nuclear warheads here, and not just a single dozen of them,” Lukashenko said in an apparent reference to the tactical weapons, adding that the West failed to track their deployment.

“They haven't even noticed when we brought them here,” he added.

Earlier this year, Russian and Belarusian militaries held joint nuclear drills. They involved Belarus’ Russia-supplied Iskander short-range ballistic missiles that can be fitted with nuclear warheads and warplanes equipped to carry nuclear bombs.

The deployment of tactical nuclear weapons to Belarus, which has a 1,084-kilometer (673-mile) border with Ukraine, would allow Russian aircraft and missiles to reach potential targets there more easily and quickly if Moscow decides to use them. It also extends Russia’s capability to target several NATO allies in Eastern and Central Europe.

During the signing of the security pact on Dec. 6, Lukashenko asked Putin to deploy more advanced weapons in Belarus, including the Oreshnik intermediate range ballistic missile that Russia used for the first time last month against Ukraine.

Putin responded that Oreshnik missiles could be deployed to Belarus in the second half of 2025, adding that they will remain under Russian control but Moscow will allow Minsk to select the targets.

“We will determine targets for them here in Belarus, not the Russians,” Lukashenko said Tuesday. “And we will push the button together if needed, God forbid.”

He noted that Belarus has about 30 facilities for nuclear-capable ballistic missiles left over from the Cold War era when it was part of the USSR and hosted Soviet nuclear weapons.

He added that a Belarus manufactures the large vehicles that serve as mobile launchers for Russian ballistic missiles, including Oreshnik.

Putin has hailed Oreshnik’s capability, saying its multiple warheads that plunge to a target at Mach 10 are immune from interception and are so powerful that the use of several of them in one conventional strike could be as devastating as a nuclear attack.

Speaking Tuesday, Putin charged that “a sufficient number of these advanced weapon systems simply makes the use of nuclear weapons almost unnecessary.”

Russia’s missile forces chief declared that the missile, which can carry conventional or nuclear warheads, has a range allowing it to reach all of Europe.

The revamped nuclear doctrine that Putin signed last month formally lowered the threshold for Russia’s use of its nuclear weapons, a move that follows U.S. President Joe Biden’s decision to let Ukraine strike targets inside Russian territory with American-supplied longer-range missiles.

The doctrine says Moscow could use nuclear weapons “in response to the use of nuclear and other types of weapons of mass destruction” against Russia or its allies, as well as “in the event of aggression” against Russia and Belarus with conventional weapons that threaten “their sovereignty and/or territorial integrity.”