Belarusian President Alexander Lukashenko warned on Monday of a joint response with Russia to military exercises involving troops from NATO member countries in neighbouring Ukraine.
Lukashenko, who gave no details of the response, also blamed the West for what he said was a looming humanitarian catastrophe this winter after migrants were left stranded and freezing on the Belarusian-Polish border.
Ukraine is not a member of the North Atlantic Treaty Organisation but has long sought closer integration with Western militaries in the hope of one day joining the alliance, a move opposed by Belarus' main ally, Russia.
Ukraine began joint military exercises with U.S. and other NATO member troops last week, while Russia and Belarus held large-scale drills that alarmed the West.
Lukashenko said he had discussed the situation in Ukraine with Russian President Vladimir Putin several times, and the Kremlin said on Monday that expansion of NATO military infrastructure in Ukraine crossed a red line for Putin.
"You see, they are dragging NATO troops there, to Ukraine. Under the guise of training centres, they are actually creating bases. The United States is creating bases in Ukraine. It is clear that we need to react to this," Lukashenko said at a meeting with officials in the presidential palace in Minsk.
"The Russian president and I have held and are holding consultations on this issue and have agreed that some action should be taken there. Otherwise, tomorrow we will have an unacceptable situation right on the border between Belarus and Russia."
Relations between Belarus and the West have deteriorated since Lukashenko cracked down on mass protests following a disputed election in August 2020, triggering U.S., European Union and British sanctions but support from Moscow.
Belarus and its EU neighbours have also traded blame over the plight of migrants. The EU has accused Minsk of encouraging migrants, mainly from Iraq and Afghanistan, to cross the borders in retaliation for the sanctions.
Three migrants died on the Polish side of the border and one more just inside Belarus this month. A fifth death - of an Iraqi man on Poland's side of the border, from a suspected heart attack, was reported on Friday.
Lukashenko said Belarus had treated the migrants well.
"Yes, we dressed them, we brought them some firewood and some shawls. But they would freeze in winter," Lukashenko said.
"In short: it's a humanitarian catastrophe on the border."
