Lithuania on Friday closed two of its six border checkpoints with Belarus in a move it announced earlier this month citing the security risk posed by Russia's Wagner mercenary group.
"Both Sumsko and Tvereciaus border checkpoints were shut at midnight," the spokeswoman of the border guard service Lina Laurinaityte-Grigiene told AFP.
Officers laid road spikes at the closed checkpoints and will proceed to erect fences with barbed wire in the area on Friday, she added.
Lithuania, a member of NATO's eastern flank, responded to escalating tensions between the neighbours, with Vilnius warning of a provocations threat by Minsk.
But the officials in Vilnius said the decision will also help control smuggling, as the remaining four border checkpoints have the X-ray systems to detect illegally transported goods, mainly cigarettes.
The decision is also meant to curb travelling across the border for shopping or family visits.
In the first half of 2023, Lithuanian citizens crossed the border with Belarus 230,000 times.
But Vilnius has been warning that Minsk may try to recruit those travellers for espionage, exert psychological pressure, or even blackmail them by performing checks on their phones and social media.
The Lithuania-Belarus ties had been tense for years, but they further deteriorated after Belarusian 2020 presidential elections, widely slammed as rigged.
Belarus criticised the decision to close checkpoints, calling it "far-fetched".
"Lithuania, by taking such decisions, purposefully and deliberately creates artificial barriers on the border to serve its political ambitions," Belarus' border force said on social media Wednesday.
Both Poland and Lithuania have erected fences on their borders with Belarus and Russia.