By Laura Gozzi & Paul Kirby, BBC News
A Russian Ilyushin Il-76MD airplane. Photo: Nicolas Economou / NurPhoto / NurPhoto via AFP
A Russian Ilyushin-76 military transport plane has crashed in the southern Belgorod region bordering Ukraine.
Russia's ministry of defence said 65 captured Ukrainian military were on the plane heading to Belgorod region for a prisoner exchange.
None of the details surrounding those on board can be independently verified.
Ria Novosti news agency said another nine people were on the plane, including six crew.
Ukraine's general staff, quoted by the Ukrainska Pravda website, said the plane was transporting missiles for Russia's S-300 air defence systems. It made no mention of prisoners of war.
Video shared on social media showed a plane going down followed by an explosion and a fireball near the village of Yablonovo, 70km to the north-east of the city of Belgorod, about 11am local time (08:00 GMT).
The regional governor in Russia's Belgorod region, Vyacheslav Gladkov, said the plane crashed in a field near a residential area and that everyone on board had died.
Some Ukrainian media suggested initially that the Il-76 may have been downed by Ukrainian forces, but those reports were later deleted.
Ukraine's general staff told BBC Ukrainian that it did not have accurate information about the situation and that it was investigating the circumstances.
The Ukrainian government body in charge of prisoners of war warned that Russia was "actively carrying out special information operations against Ukraine, which are aimed at destabilising Ukrainian society".
Andrei Kartapolov, the chairman of Russia's parliamentary defence committee, claimed later that there had been a second plane in the air transporting 80 Ukrainian prisoners, although that plane had then changed course.
"There can now be no talk of any other [prisoner] exchanges," Mr Kartapolov told Russian TV.
Russian presidential spokesman Dmitry Peskov said the Kremlin was aware of the crash but refused to go in to details.
A nationwide air raid alert was briefly in place across Ukraine shortly after news of the Il-76 crash emerged.
Belgorod, which is located approximately 25 miles (40km) north of the border with Ukraine, has suffered dozens of casualties from air strikes and drones since the war in Ukraine began.
In December, 25 people were killed and 100 were injured following an air strike - although Ukraine insisted that only military infrastructure had been targeted and blamed Russian air defences for fragments falling on the city.
- This story was first published by the BBC.
