Belarus military units were testing their capacity to "go on the alert, move to predetermined zones and undertake combat training," the ministry said in a statement.

"The aim is to evaluate the readiness and ability of troops to react rapidly to a possible crisis," it continued, describing the manoeuvres as a "surprise" exercise.

It published photos of columns of vehicles, including tanks, moving along roads.

The exercise will be closely watched by Kyiv, which has repeatedly accused Belarus of planning to send troops into Ukraine to help Russia's military operation against its pro-Western neighbour.

Belarus has been ruled with an iron fist by strongman Alexander Lukashenko, an ally of Russian President Vladimir Putin, for nearly 30 years. The country serves as an air and logistics base for Moscow.

Nevertheless, not all Belarusians are in favour of participation, however indirect, in the current conflict and there have been acts of sabotage in recent months and several suspects have been arrested.

In 2020, Belarus was rocked by protests over the allegedly fraudulent re-election of Lukashenko, who ordered a ferocious crackdown on the dissent.