This happened after Russia and its close ally Belarus announced the start of new joint military exercises.
Belarus, which has been a key ally of Russia throughout the conflict, last February allowed Moscow’s forces to launch its offensive from Belarusian territory.
Its defense ministry said the air force exercises would include joint “tactical” flights and every airfield in Belarus would be involved.
“The exercise is of a purely defensive nature,” Pavel Muravyko, First Deputy State Secretary of the Security Council of Belarus, said in comments by the Defense Ministry on Sunday.
The United States-based Institute for the Study of War said in an analytical note on Monday that the risk of a new invasion from Belarus was “low” and that “the risk of direct Belarusian involvement was very low”.
Meanwhile, UN nuclear watchdog chief Rafael Grossi was expected to deploy observer missions to nuclear power plants across the country in Ukraine on Monday, which has been a major concern during Russia’s invasion.