President Alexander Lukashenko said Thursday that Belarus would join the offensives in Ukraine "only if attacked" first by Kyiv's army.
"I'm ready to fight together with the Russians from the territory of Belarus in one case only: if so much as one soldier from (Ukraine) comes to our territory with a gun to kill my people," the veteran strongman told a rare press conference with foreign journalists in Minsk.
"This applies to our other neighbors," Lukashenko said. "If they commit an aggression against Belarus, our response will be the most cruel. The most cruel!"
Minsk allowed the Kremlin to use the country as a launching pad for its military operation against Kyiv last February.
Belarus still hosts an undeclared number of Russian troops but Lukashenko has promised not to send his forces — estimated at between 60,000 and 70,000 — over the southern border to Ukraine.
Despite Lukashenko's repeated promises, fears have been building that his troops could also intervene.
But the longtime leader said, "I do not plan to send my people, my soldiers (there)," Lukashenko said.
Fears have also grown that Belarus could announce a Russian-style mobilization.
But he did say Minsk was testing some of its mobilization abilities and was taking into account Russian blunders in their drive.
"It will not be tomorrow. But we need to be ready if anything," he said.
Lukashenko was due to meet Putin on Friday.
He said the pair would discuss a joint regional force announced in October, that also saw several thousand Russian servicemen arrive in the ex-Soviet nation.
Lukashenko said he had asked Putin for an extra Russian division that would fall under his leadership.
Allies 'legally and morally'
"If there will be aggression, these people would be brought into the Belarusian army."
He gave no further details.
Putin last month said he backed plans to set up joint military training centers with Belarus.
Lukashenko said the force is purely defensive.
The two countries also regularly carry out joint military exercises.
It is unknown how many Russian soldiers are stationed in Belarus.
Lukashenko, in power since 1994, defended his role a year ago, when Russian troops launched their offensive on Ukraine, including from Belarusian territory.
He echoed the Kremlin in saying that Russia was "forced" to do so and blamed Ukraine and the West for the conflict.
"Don't forget that Russia is our ally, legally, morally," he said.
Asked if he could somehow influence the Russian leader, he said:
"If he believes he is right then you can't convince him."
Lukashenko also hit out at neighboring Poland and Lithuania — EU members — for closing border crossings with Belarus and vowed retaliation.
"It is an economic provocation," he said. "We are forced to respond."
Warsaw closed the Bobrowniki border checkpoint last week, citing "growing tensions" with Belarus.