The Zaporizhye nuclear power plant is the largest in Europe. Wikipedia Ukrainian Prime Minister Arseny Yatseniuk said Wednesday that there had been an accident at a nuclear plant in southeastern Ukraine, Reuters reports.

"I know that an accident has occurred at the Zaporizhye NPP," Yatseniuk said, asking new energy minister Volodymyr Demchyshyn to make clear when the problem would be resolved and what steps would be taken to restore normal power supply across Ukraine.

The news agency Interfax Ukraine said the problem had occurred at bloc No 3 — a 1,000-megawatt reactor — and the resulting lack of output had worsened the power crisis in the country. Interfax added that the bloc was expected to come back on stream on Friday.

There are reports that the damage is minor, with no damage to the reactor. Ukraine gets about half its power from nuclear plants.

Ukraine's Zaporizhe nuke plant unit 3 was shut down Nov 28, due back on line Dec. 5, Interfax reports, without offering details of accident — greg white (@whitegl) December 3, 2014

"Assuming it is indeed as minor as now appears, suggest Yatsenyuk goes on a 'how to talk about nuclear incidents without sowing panic' course," Guardian journalist Shaun Walker, who has covered the conflict in Ukraine, tweeted.

The six units of the Zaporizhia NPP. Wikipedia

Ukraine voted on a new government on Tuesday night.

Under President Petro Poroshenko and Yatseniuk, Kiev has cut aid to the eastern regions held by pro-Russian rebels since soon after protesters toppled Kiev's pro-Moscow president in February.

Fighting has continued despite a cease-fire reached Sept. 5. In the rebel stronghold of Donetsk a senior separatist figure said rival sides agreed a new local truce from 10 a.m. ET around the city airport.

"But this is 65th time we agree about this. I don't rule out that there is going to be 66th time," Andrei Purgin said. Sounds of fighting abated but did not stop. Kiev said rebels renewed attacks on the airport in the evening.

Russia acknowledges supporting the separatists but denies Western charges of being a party to the armed conflict.

This post will be updated with details as they arrive.