Belarusian President Alexander Lukashenko accused neighbouring Ukraine on Tuesday of sending 15,000 troops to the border area to build defences and conduct reconnaissance, actions that he called "provocations".
Lukashenko allowed his close ally Russia in February to use Belarus as a staging post for its invasion of Ukraine. However, he has said Belarus is not a party to the conflict and that its own forces are not involved.
In comments carried by the state news agency BelTA, Lukashenko said the Ukrainian unit brought up to the border had blocked roads and was setting up checkpoints and firing positions.
"In a word, has not only barricaded itself, but built a wall. Constantly conducting optical, radio-electronic and radio-technical reconnaissance of our territory, troops and objects," Lukashenko said.
"Often with their drones violating the line of the state border. And at the same time, they worry and worry: 'Oh, don't let Belarus enter the war'. And there are constant provocations at the border."
Ukrainian officials did not immediately respond to a request for comment.
Lukashenko said his country was involved in the conflict only to prevent it spreading into Belarus and to "prevent an attack on Belarus under the guise of a special military operation from Poland, Lithuania and Latvia".
"As I have said, nobody will shoot the Russians in the back from the territory of Belarus," he said.
Belarus's three western neighbours are all part of the NATO transatlantic alliance, which is helping Ukraine to defend itself against Russia with weapons and intelligence but says it will not take a direct part in the conflict.
