Exiled Belarusian opposition figures say a Russian military plane has been damaged in a drone attack near the capital, Minsk.
Aliksandr Azarov, leader of Belarusian anti-government organisation BYPOL, claimed responsibility for the attack on Telegram.
The Beriev A-50 early warning aircraft was struck by multiple blasts near the Machulishchy airbase.
It comes amid increased cooperation between Minsk and Moscow.
The strikes damaged front and central parts of the aircraft as well as its radar and antenna, BYPOL said on Telegram.
“These were drones. The participants of the operation are Belarusian”, Mr Azarov said.
Speaking to the BBC, Franak Viacorka, an adviser to Belarusian opposition leader, said the attack was “creative” and “sophisticated”.
“It was very brave because Belarusians are in a situation of the total terror”, he told BBC News.
He added that the opposition party was “definitely helped by locals, helped by military” to cause damage to the plane.
However, it is not possible to confirm the opposition’s account of what happened.
Both the Russian and Belarusian departments of defence are yet to publicly comment on the incident.
BYPOL, the group that has claimed responsibility for the strike on the aircraft, consists of former law enforcement officers now opposed to President Alexander Lukashenko’s office.
It has been listed as a terrorist organisation by Mr Lukashenko’s government.
While Belarus has not directly become involved in the war in Ukraine, Mr Lukashenko allowed Russian troops to launch into Ukraine through Belarus.
The two countries have also been participating in joint military training exercises over recent months.