Belarusian President Alexander Lukashenko inadvertently confirmed on Monday that four military aircraft had been shot down over Russia last week near the borders of Ukraine and Belarus, saying Minsk had responded by putting its armed forces on high alert.
The incident came as Ukraine prepares for a counter-offensive against Russia's invading forces.
The respected Russian news outlet Kommersant reported on Saturday that a Russian raiding party comprising an Su-34 fighter-bomber, an Su-35 fighter, and two Mi-8 helicopters had been shot down in an ambush near Klintsy in Russia's Bryansk region.
It said they had been due to attack targets in the Chernihiv region of Ukraine, directly over the border.
Warplane crashes reported
The Russian state news agency TASS said on Saturday that a Russian Su-34 warplane had crashed, but did not specify a cause, and cited emergency services as saying an engine fire had brought down a helicopter.
It did not mention the Su-35 or a second helicopter, although several heavily followed Russian pro-war military bloggers also said the four aircraft had been shot down.
The Pul Pervovo Telegram channel, a Belarusian state outlet that reports on Lukashenko's activities, said on Monday that he had visited an air force command base, and quoted him as saying:
"Three days after the events near us - I mean in the Bryansk region when four aircraft were shot down. We are forced to respond. Since then, we, our troops, have been on high alert."
"Three days after the events near us - I mean in the Bryansk region when four aircraft were shot down. We are forced to respond. Since then, we, our troops, have been on high alert."
Alexander Lukashenko
Lukashenko's reported visit to the base was his first public appearance in almost a week, following speculation over the health of the 68-year-old leader.
The Russian Defense Ministry did not respond to a request for comment on the Kommersant report.
There was also no official response to the incident from Ukraine, which usually declines to comment on reports of attacks inside Russia.
However, in a Twitter post, Mykhailo Podolyak, a senior adviser to Ukrainian President Volodymyr Zelensky, on Saturday called the incident "Justice ... and instant karma."