Two bridges collapsed in different Russian regions bordering Ukraine, derailing trains and killing at least seven people and injuring dozens, Russian authorities said early on Sunday.

Reuters could not independently confirm whether the incidents in the neighbouring regions were related.

The collapse in the Kursk region occurred early on Sunday while a freight train was crossing the bridge, Alexander Khinshtein, acting governor of the region, and Russian Railways said on Telegram.

"Part of the train fell onto a road underneath the bridge," Khinshtein said. He added that the locomotive caught fire, which was quickly extinguished. One of the drivers sustained leg injuries, and he and the team operating the train were taken to a local hospital, Khinshtein added.

He posted a photo of derailed carriages on a damaged bridge over a road.

That followed an earlier incident later Saturday in which seven people were killed and 69 injured when a highway bridge collapsed onto railway tracks, derailing an approaching train in the Bryansk region, Russian emergency ministry and regional officials said.

Russia's Railways initially posted on the Telegram messaging app that the Bryansk bridge collapse was the result of an "illegal interference in the operation of transport," but the post was later removed.

Bryansk Governor Alexander Bogomaz said on Telegram that 47 people were hospitalized. Three children were among those injured with one in serious condition, he said.

Andrei Klishas, a senior member of the Federation Council, Russia's upper chamber of parliament, said on the Telegram messaging app that the incident in Bryansk shows that "Ukraine has long lost the attributes of a state and has turned into a terrorist enclave."

The areas in Russia's south have been subject to frequent attacks by Ukraine during the war that Russia started with its full-scale invasion more than three years ago.

Russia's Baza Telegram channel, which often publishes information from sources in the security services and law enforcement, reported, without providing evidence, that according to preliminary information, the Bryansk bridge had been blown up.

Reuters could not independently verify the Baza report. There was no immediate comment from Ukraine.

Since the war began in February 2022, there have been continued cross-border shelling, drone strikes and covert raids from Ukraine into the Bryansk, Kursk and Belgorod regions that border Ukraine.

Russia's Ministry of Emergency Situations said on Telegram that efforts to find and rescue victims in the Bryansk incident continued throughout the night, and that some 180 personnel were involved in the operation.

Among those killed was the locomotive driver, Russia's state news agencies reported, citing medics.

Social media pictures and videos showed passengers trying to help others climb out of the Bryansk train's damaged carriages in the dark and firefighters looking for ways to reach passengers.

The train was going from the town of Klimovo to Moscow, Russian Railways said. It collided with the collapsed bridge in the area of a federal highway in the Vygonichskyi district of the Bryansk region, Bogomaz said. The district lies some 100 kilometres from the border with Ukraine.

U.S. President Donald Trump has urged Moscow and Kyiv to work together on a deal to end the war, and Russia has proposed a second round of face-to-face talks with Ukrainian officials in Istanbul on Monday.

Ukraine has not committed to attending the talks, saying it first needed to see Russia's proposals, while a leading U.S. senator warned Moscow it would be "hit hard" by new U.S. sanctions.

WATCH | How Trump's recent criticism of Putin may signal U.S. policy shifts:

Trump vs. Putin: Is the U.S. finally fed up with the Russia-Ukraine war?

U.S. President Donald Trump's stance on the Russia-Ukraine war and Putin has changed drastically over time. Andrew Chang explores how Trump's recent criticism of Putin may signal U.S. policy shifts. Then, can one judge overrule Trump?