The Ukrainian air force shot down a Russian "spy" plane that can spot targets up to 650 kilometers away, as well as a command center plane that relays information to troops on the ground.
The aircraft are essential tools to help orchestrate Russian movements on the battlefield in Ukraine. Their destruction, if confirmed, would be a historic achievement for Ukraine in the nearly two-year-old war, as fighting along the front line has largely been reduced to trench warfare and artillery.
Russia has largely asserted its air dominance during the war, while Ukraine fights with its fleet of Soviet-era fighter jets against Moscow's more modern aircraft.
General Valeriy Zaluzhnyi, the commander-in-chief of Ukraine's armed forces, did not say how the two planes, a Beriev A-50 and an Il-22, were downed, but Ukraine has received sophisticated air defense systems from its Western allies.
Zaluzhnyi also did not say where the intercepts took place, although he attached a video to his social media post with an aircraft radar showing two targets disappearing over the Sea of Azov, which lies between Ukraine and Russia, north of the Crimean Peninsula and Black Sea.
Moscow has not yet reacted to this catastrophic loss. Russian bloggers said both planes had been mistakenly hit by Russian missiles, although they provided no evidence of this. They claimed the Il-22 was damaged but made a successful landing.
The A-50, which is equipped with a large radar, usually carries a crew of 15. The Russian Air Force reportedly has a fleet of nine such aircraft.
A February 2023 drone strike on an airfield in Belarus damaged a parked A-50, but Russian and Belarusian officials described the damage as minor.