The side of one carriage of the passenger train was ripped open in the collision on the Bekasovo-Nara line, near the town of Naro-Fominsk and 24 miles from central Moscow.

Viktor Yatsenko, an emergencies ministry official, said 45 people had been hurt, 15 of them seriously.

Itar-Tass reported that police had said 16 carriages on the freight train derailed and smashed into the passenger train.

The scene of the crash near Bekasovo station

One of the drivers of the passenger train was quoted by RIA as saying: "We tried to use an emergency brake.

"We couldn't see anything ahead, there was lots of dust. Visibility was zero."

Three carriages holding people on the passenger train, which was en route from Chisnau in Moldova to Moscow, reportedly overturned.

Russian television footage showed passengers clambering from a train that was tilting over a grassy bank.

Rescue co-ordinator Vadim Andronov told Itar-Tass that the death toll was likely to rise.

"One of the carriages of the passenger train was crushed by the freight train wagons," he said.

"Rescuers are working to pull out injured people being crushed by the wagon."

It was no immediately clear what caused the collision.

Service on the line has been suspended.