Ukrainian officials say repairs to the only operational reactor at the Chernobyl nuclear power station will have to be postponed for at least two weeks, because of serious energy shortages.

The nuclear regulation authorities in Ukraine had ordered the reactor to be shut down today Tuesday, warning that some safety equipment needed upgrading or replacing.

But the energy ministry said this would mean power cuts on a massive scale across the country, where thousands of towns and villages are already without electricity for several hours a day in freezing temperatures.