Belarus has closed its border with Ukraine, claiming that arms are being smuggled into the country.

Belarus President Alexander Lukashenko says it is part of an attempt by outside powers to overthrow his authoritarian regime.

Mr Lukashenko claimed – without providing proof – that his security services had uncovered a foreign-backed terrorist sleeper cells plotting to oust him from power.

“They have crossed the line. We cannot forgive them,” he said.

He alleged the weapons were being shipped to terrorist cells funded by Germany, Lithuania, Poland, Ukraine and the US.

“A huge amount of weapons is coming from Ukraine to Belarus. That’s why I ordered border-security forces to fully close the border with Ukraine,” Lukashenko said, at a ceremony marking the country’s 30 years of independence following the collapse of the Soviet Union.

Belarus shares a border with Ukraine in the south. It borders Poland and Lithuania in the west, Latvia in the north, and Russia in the east.

The move deepens a standoff between Belarus, the EU, the UK and the US, all of which have imposed sanctions on Belarus.

In May his government prompted international outrage when it forced a Ryanair flight to land and arrested of a government critic who was onboard.

Lukashenko has also banned all citizens of Belrus from going abroad.

Many dissidents have left Belarus since a disputed election last year.

In its statement on the Telegram messaging service, the border committee says it has received “many requests to leave Belarus on the strength of residence permits [issued] by foreign countries”.

Only those with permanent residence in foreign countries – not temporary – are allowed to leave Belarus now, it says. The border committee blamed the measures on the coronavirus pandemic.

President Alexander Lukashenko’s harsh crackdown on opponents since his disputed August 9 election victory has sent many into exile or to jail.