A highway bridge over a railway in the Bryansk region was blown up at 10.50pm on Saturday night just as a passenger train carrying 388 passengers to Moscow was passing underneath, Russian investigators said.
Four hours later, a railway bridge over a highway was blown up in the neighbouring Kursk region showering the road with parts of a freight train, the investigators said.
Russia's Investigative Committee, which probes serious crimes, linked the incidents and said explicitly that both bridges were blown up.
In the Bryansk region, social media pictures and videos showed passengers trying to climb out of smashed carriages in the dark. Part of the passenger train was shown crushed under a collapsed road bridge and wrecked carriages lay beside the lines.
"The bridge was blown up while the Klimovo-Moscow train was passing through with 388 passengers on board," Alexander Bogomaz, the region's governor, told Russian television.
The Russian regions bordering Ukraine have been subject to frequent attacks by Ukraine since Russia invaded Ukraine in February 2022. Both sides accuse the other of targeting civilians, and both deny such accusations.
There was no immediate comment from Ukraine on the incidents, which took place just a day before the United States wants Russia and Ukraine to sit down to direct talks in Istanbul to discuss a possible end to a war which, according to Washington, has killed and injured at least 1.2 million people.
Ukraine's HUR military intelligence agency said on Sunday that an explosion had derailed a Russian military train hauling cargo and fuel trucks near the settlement of Yakymivka, in a Russian-controlled part of Ukraine's Zaporizhzhia region.
The agency did not claim responsibility or attribute the explosion to anyone, though Ukraine has in the past claimed a series of attacks deep into Russia.
Russian politicians lined up to blame Ukraine, saying it was clearly sabotage aimed at derailing the peace talks which the United States has demanded.
"This is definitely the work of the Ukrainian special services," the chairman of the defence committee of the lower house of the Russian parliament, Andrei Kartapolov, told the SHOT Telegram channel.
"All this is aimed at toughening the position of the Russian Federation and stoking aggression before the negotiations. And also to intimidate people. But they won't succeed."
President Vladimir Putin was briefed on the bridge blasts by the Federal Security Service (FSB) and the Emergency Ministry throughout the night, the Kremlin said. Putin also spoke to the governor of Bryansk, Alexander Bogomaz.
US President Donald Trump has demanded the sides make peace and he has threatened to walk away if they do not - potentially pushing responsibility for supporting Ukraine onto the shoulders of European powers.
But as politicians talk of peace negotiations, the war is heating up, with swarms of drones launched by both Russia and Ukraine and Russian troops advancing at key points along the front in eastern Ukraine.
Ukraine has not committed to attending the talks in Turkey, saying it first needed to see Russia's proposals, while a leading US senator warned Moscow it would be "hit hard" by new US sanctions.
