Lithuania and Latvia also boost Belarus-border security

The move was due to "geopolitical circumstances", the Lithuanian government said.

It was designed to help concentrate the numbers of border guards at the remaining four crossing points, Lithuania's deputy transport minister Agnė Vaiciukeviciūte added.

Border-guard leave has been cancelled, with army and police being asked to help, Lithuanian media also reported.

Lithuania has stopped some 1,540 irregular migrants coming via Belarus so far this year.

It has erected signs on its side of the border saying: "Do not risk your safety — do not travel to Belarus. You may fail to come back".

And the country's border-guard chief, Rustamas Liubajevas, estimated the Russian Wagner mercenary group has stationed up to 4,500 fighters in Belarus bases near its frontiers with EU and Nato neighbours.

Lithuania's move came one day after Latvia said it was sending soldiers to the Belarus border due to "information about a possible increase in hybrid threats".

Almost 100 migrants had tried to cross in the 24 hours before the announcement on Tuesday, Latvia said.

"We have seen that this summer the pressure from Belarus is not decreasing, but gradually increasing," Latvian prime minister Krišjānis Kariņš said.

"We are simply increasing our presence and sending a clear signal to both our own society and the Belarusian authorities that this is no joke," he added.

Poland, last week, said it was sending 10,000 soldiers to the Belarus border for similar reasons.

For its part, the Belarus border-guard service complained about Lithuania's crossing-point closures.

"With these decisions, the Lithuanian side is purposefully and deliberately setting up artificial barriers on the border to serve its political ambitions", it said in a statement.

Belarus flew in thousands of African and Middle Eastern migrants and forced them across the border into EU countries in summer 2021 in a "hybrid" revenge against Western sanctions.

But even after the 2021 crisis abated, there were still 16,000 attempted irregular crossings into Poland last year and 19,000 so far this year.

The Wagner group partly relocated to Belarus after its leader, Yevgeny Prigozhin, mutinied against the Russian army in June.

Both Prigozhin and Wagner's future remain uncertain, but Wagner's combat units and political-spin departments in Africa have continued to operate since the insurrection.

It has also trained Belarusian soldiers and registered as "an educational organisation" in the Asipovichy district in the eastern Belarusian region of Mahilyou.

And the Prighozin and Wagner-linked Concord Management and Consulting company has registered in the same spot, indicating that the Russians have come to stay.