Some experts have predicted shortages continuing until next year.

He added Ukraine had "absolutely no incentive to sabotage the Istanbul summit".Russian President Vladimir Putin was briefed on the incidents throughout the night, the Kremlin said.

Pictures online from Bryansk showed mangled carriages and passengers helping each other climb out of the wreckage in the dark.Moscow's interregional transport prosecutor's office said an investigation had been launched.Authorities said the train's locomotive and several cars derailed when the road bridge fell on to it.

Additional emergency workers, as well as rescue equipment and light towers for carrying out work at night have been sent to the area, according to Russian news agency TASS.The train was going from the town of Klimovo to Moscow and was in the Vygonichsky district when the collapse happened, officials said.

Passengers were evacuated and guided to a meeting point at a nearby station, Moscow Railway said, adding: "They will be able to continue their journey on a specially formed reserve train" travelling from Bryansk to Moscow.

The first incident took place about 100km (62 miles) from the Ukraine border.bringing in a younger audience and providing a space for all voices was "really making the difference".

"I'm seeing younger people, more ethnically diverse people, a lot of really good queer representation happening... and that's really, really important," she said."We're seeing a more modern Wales perhaps being represented whilst not losing that classic literary approach.

"We have a really rich national history of literature and there's nothing wrong with being middle-class, there's nothing wrong with really literary writing like classic books."There's just a place for all of our different types of writing. That's the most important thing."