A military transport plane that Russia said was carrying 74 people, including 65 Ukrainian prisoners of war to be swapped, crashed Wednesday in a border area near Ukraine. All aboard were killed, according to a regional Russian governor.

It wasn’t immediately clear what caused the crash in the Belgorod region, and The Associated Press could not confirm who was aboard. Ukrainian officials cautioned against sharing unverified information.

Video of the crash posted on social media showed a plane falling from the sky in a snowy, rural area, and a massive ball of fire erupting where it apparently hit the ground.

Firefighters, ambulances and police rushed to the site in the Korochansky district of Belgorod, state news agency Tass reported, citing a local emergency services official.

The Russian Defense Ministry said the POWs were being transported to the region for a prisoner exchange.

Belgorod Gov. Vyacheslav Gladkov didn’t specify who was on the plane.

Two senior Russian lawmakers alleged, without providing evidence, that the plane was brought down by missiles launched by Ukrainian forces.

Russia has largely ensured its air dominance during the war, which marked its 700th day on Wednesday, against Ukraine's fleet of Soviet-era warplanes. But the Russian air force has suffered a string of crashes that some observers have attributed to a higher number of flights amid the fighting in Ukraine.

At the same time, Kyiv has boasted recently about shooting down two Russian command and control planes, which would be a major feat for Ukraine if true. Cross-border attacks on Russia’s Belgorod region also have been ramped up lately, with the deadliest one killing 21 people in late December.

Shortly before the crash, Gladkov said on his Telegram channel that a “missile alert” had been triggered in the region and warned residents to take shelter.

Ukraine’s Coordination Headquarters for the Treatment of Prisoners of War said it was looking into the crash but did not immediately provide any information. Instead, it cautioned against sharing “unverified information.”

“We emphasize that the enemy is actively conducting information special operations against Ukraine aimed at destabilizing Ukrainian society,” it said in a statement on Telegram.

The Russian Defense Ministry said a special military commission was on the way to the crash site. In addition to the POWs, the Il-76 cargo plane was carrying three people accompanying them and a crew of six, the ministry said.

President Vladimir Putin’s spokesman Dmitry Peskov said on his call with reporters that he could not comment on the crash because he did not have enough information about it.

The Il-76 is designed to carry up to 225 troops, cargo, military equipment and weapons, according to Russia's military export agency.

The war's 1,500-kilometer (930-mile) front line has been largely static amid a second winter of fighting. As both sides seek to replenish their weapons stockpiles, the war recently has focused on long-range strikes.

Earlier, Ukrainian President Volodymyr Zelensky said a major Russian missile attack on Tuesday had killed 18 people and injured 130.

The barrage, employing more than 40 ballistic, cruise, anti-aircraft and guided missiles hit 130 residential buildings in three Ukrainian cities, “all ordinary houses,” Zelensky said on X, formerly Twitter.

Russia’s onslaught, which included targets in the capital Kyiv and second-largest city Kharkiv, was the heaviest in weeks and lent weight to Zelensky’s appeals for Western allies to provide more military aid.

“This year, the main priority is to strengthen air defense to protect our cities and towns, as well as defend front-line positions,” Zelensky posted late Tuesday.

Analysts say Russia stockpiled missiles to pursue a winter of aerial bombardment, while Ukraine has sought to strike inside Russia with new types of drones.

Russia may have employed decoy missiles in Tuesday’s attack in an effort to open up holes in Ukraine’s air defenses, a US think tank said.

The Washington-based Institute for the Study of War said Moscow is likely trying to acquire more ballistic missiles from foreign countries, including Iran and North Korea, because they may be more effective in some circumstances.

A further barrage of Russian S-300 missiles struck residential districts of Kharkiv late Tuesday, injuring nine people and damaging residential buildings, regional Gov. Oleh Syniehubov said.

Russia denies its forces strike civilian areas, although there is substantial evidence to the contrary.

The Russian Defense Ministry said that air defenses shot down four Ukrainian drones over the Oryol region of western Russia early Wednesday.

Oryol Mayor Yuri Parakhin said that several drones were downed over the city. He said there were no casualties, but windows were shattered in apartment buildings.

Another Ukrainian drone was downed early Wednesday over the Belgorod border region, according to Gladkov. He said there were no casualties or damage.

Ukraine’s allies have promised to keep sending military aid packages, even though their resources are stretched. Help from the United States, by far Ukraine’s single biggest provider, has also hit political snags.

The German defense ministry announced Wednesday that it plans to send six Sea King Mk41 helicopters to Ukraine.