Ukraine and Russia are waging a public relations war over repairs at the Chernobyl nuclear power plant. Russian forces took control of the plant last week and, on Tuesday, the facility’s safeguard monitoring system stopped transmitting.

On Thursday morning, Russia said Belarusian specialists had restored power at the facility, a claim that Ukraine denies. Ukrenergo, Ukraine’s national electricity grid operator, said crews are waiting to enter the plant to make repairs but cannot do so until the two sides agree to a ceasefire. The operator also reportedly rejected offers of help from Belarus.