Ukrainian President Volodymyr Zelensky has accused Moscow of "playing with the lives of Ukrainian prisoners", after a deadly plane crash in western Russia.

He demanded an international inquiry after Wednesday's crash in the Belgorod region near Ukraine's border.

Russia said there were no survivors after Kyiv had downed the Il-76 plane with 65 Ukrainian prisoners of war, six Russian crew and three escorts.

Moscow claimed the Ukrainians were being flown for a prisoner exchange.

Ukraine's military intelligence (GUR) said it had not been told to ensure safe airspace, as on previous occasions.

The GUR comments have been seen as a tacit acknowledgement that Ukraine shot the military transport plane down, although it stressed it had no reliable information about who was on board and warned the incident may have involved "planned and deliberate actions by Russia".

In his video address late on Wednesday, President Zelensky said it was "obvious that the Russians are playing with the lives of Ukrainian prisoners, with the feelings of their relatives and with the emotions of our society".

The Ukrainian leader, who has cancelled a planned regional trip linked to his birthday on Thursday, stressed that "all clear facts must be established".

Kremlin spokesman Dmitry Peskov condemned the downing of the plane as a "monstrous act", according to Russian news agencies. He told reporters that if Mr Zelensky meant an international inquiry into "the criminal actions of the Kyiv regime", it was definitely needed.

Video shared on social media showed a plane going down followed by an explosion and a fireball near the village of Yablonovo, 70km (44 miles) to the north-east of the city of Belgorod, at about 11:00 local time (08:00 GMT).

Belgorod regional governor Vyacheslav Gladkov said the plane crashed in a field near a residential area and that everyone on board had died.

Ukraine's general staff, quoted by the Ukrainska Pravda website, said initially that the plane was transporting missiles for Russia's S-300 air defence systems. It made no mention of PoWs.

None of the details surrounding those on board can be independently verified, but Ukraine's military intelligence said it was Russia's responsibility "to ensure the safety of our defenders under the agreements that had been reached".

On this occasion it said it had not been informed that the airspace had to be safeguarded "at the defined time, which is something that had happened on numerous occasions before".

"This can point to Russia's deliberate actions aimed at putting the lives and safety of the PoWs under threat," it added.

Ukraine and Russia have taken part in a number of prisoner swaps since the start of the war.

Ukrainian air force chief Mykola Oleschuk warned that throughout Wednesday Russian propaganda had tried to discredit Ukraine internationally. Ukraine had the right to destroy Russia's means of aerial attacks, he said.

Russia has repeatedly targeted Ukraine's second city Kharkiv with S-300 guided missiles from the Belgorod region in recent days.

Eight people were killed in a series of missiles strikes on Tuesday and another attack was launched overnight into Thursday.

Ahead of Wednesday's planned prisoner exchange, Ukrainian officials said the captured Russian military servicemen were "delivered to the agreed location in time to be exchanged, and they were safe there".

Russia's defence ministry said the swap had been due to take place on Wednesday afternoon at a border checkpoint 100km (60 miles) to the west of Belgorod.

The ministry said a military transport plane had taken off from Chkalovsky air base north-east of Moscow en route to Belgorod, alleging that Ukraine's air force had fired two anti-aircraft missiles from the Lyptsi area south of the Ukrainian border.

The Ukrainian government body in charge of PoWs warned that Russia was "actively carrying out special information operations against Ukraine, which are aimed at destabilising Ukrainian society".

Dmytro Lubinets, Ukraine's parliamentary human rights commissioner, appealed to Ukrainians to trust only official sources: "Do not be fooled by provocations. More detailed information will be provided later."

Andrei Kartapolov, chairman of Russia's parliamentary defence committee, claimed 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.

The biggest prisoner exchange since the start of the war took place earlier this month, when Ukraine freed 248 Russian prisoners of war and Russia released 230 people in a deal mediated by the United Arab Emirates.

More than 8,000 Ukrainians, both civilian and military, are still being held by Russia, according to Ukraine's Coordination HQ on the Treatment of PoWs, which says tens of thousands of others are still missing.

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.

Russia's war in Ukraine is grinding on as it approaches its third year.

Last week, Russia claimed to have captured a village close to the devastated city of Bakhmut, in Ukraine's eastern Donetsk region. Kyiv has not confirmed the claim.

Meanwhile, Russian air attacks have intensified in recent weeks. On Tuesday, 18 people were killed and 130 were injured in missile attacks on Ukrainian cities.