Belarus on Monday accused Poland of causing long delays at its border with the European Union by slowing the movement of trucks, alleging that Warsaw was failing to implement bilateral agreements.
Poland, a fierce critic of veteran Belarusian leader Alexander Lukashenko, in February closed one of its key border crossings with Belarus, citing security concerns, a decision Minsk called "catastrophic".
Strained ties between the two countries deteriorated sharply last year after Russia invaded Ukraine in what it called a "special military operation" and used Belarusian territory as a launch pad for the attack.
Poland has taken over a million Ukrainian refugees.
"Since Friday, a queue in front of the only accessible border crossing point on the Belarusian-Polish border, Kukuryki (Kozłowiczy), has doubled in size and now totals 1,000 vehicles," the Belarusian border committee said in a statement.
"The main reason is the failure of the Polish side to implement bilateral agreements on the passage of trucks," it said, accusing Poland of only processing 61% of the typical number of trucks crossing the border over the weekend.
Poland's border service was not immediately available to comment.
(Reporting by Reuters; Editing by Andrew Osborn)