Belarusian President Alexander Lukashenko said "terrorist sleeper cells" linked to the West and allegedly preparing a coup were dismantled on Friday.
"Terrorist sleeper cells were dismantled today," Lukashenko said, cited by his press office.
The authoritarian leader claimed the cells had ties to Germany, Ukraine, the United States, Poland and Lithuania, and plotted to "overthrow the regime by violence."
According to Lukashenko, "a huge number of weapons were pouring into Belarus from Ukraine," which prompted him to order Belarusian border guards to "permanently close the border with Ukraine".
He added that the cells' activities were coordinated via a Telegram channel dubbed "Self-defence regiments of Belarus" which had 2,500 subscribers and belonged to a German citizen.
The cells recently tried to detonate a Russian naval communication centre located in the Belarusian town of Vileika, about 100 kilometres northwest of Minsk, according to the Belarusian leader.
"All the participants in this terrorist act (...) were found within 48 hours and arrested," he said.
The German government repeatedly refused to comment on Lukashenko's allegations at a press conference.
The move comes amid heightened tensions between the Belarusian regime and the West after a Ryanair flight was forced to land in Minsk in May and a Belarusian journalist on board was detained.
The EU has gradually escalated sanctions since Lukashenko – dubbed the last dictator in Europe – won a sixth term last August in elections allegedly rigged in his favour.
Minsk announced Monday the suspension of its participation in the EU's Eastern Partnership while recalling its ambassador to Brussels in retaliation for European sanctions.
The country has allegedly used migrants to pressure neighbouring Lithuania, which has provided a safe haven to Belarusian opposition figures and is one of Lukashenko's most vocal critics.
Lukashenko’s government has harshly repressed post-election protests over the past year, the largest of which attracted up to 200,000 people.
More than 35,000 people have been detained since the demonstrations began, with thousands beaten, according to human rights groups.