Air strikes have hit critical infrastructure in central and western Ukraine, as Russia continues to target the country’s energy grid.
Sites to the south and west of Kyiv have been struck and power cuts have been reported across the country.
Ukrainian officials say many Russian cruise missiles have been intercepted by air defence systems.
Almost a third of the country’s power stations have been destroyed in a wave of air strikes since Monday last week.
On Saturday Ukrainian officials said “critical infrastructure” had been hit in the Cherkasy region, south-east of the capital Kyiv. A huge fire has been reported near the town of Smila.
There have been blackouts in Khmelnytskyi, further west. Air strikes and power disruptions are also being reported from Odesa in the south to Rivne and Lutsk in the north-west.
The Ukrainian energy distribution company said it would limit electricity supply in several regions, including Kyiv.
The government introduced restrictions on the use of power for the first time on Thursday.
Ukraine’s air force command said its defence systems had destroyed 18 Russian cruise missiles launched on Saturday morning.
President Volodymyr Zelensky’s chief of staff, Andriy Yermak, has said Russia is hoping to stop Ukraine’s liberation of territories by striking targets behind the front lines. But, he added, the attacks would only lead to an even stronger response.
On Friday Mr Zelensky accused Russia of planting mines at a hydroelectric dam in the Kherson region of southern Ukraine, which is under the control of Moscow’s forces.
He said that if the Kakhovka hydropower plant was destroyed, hundreds of thousands of people would be in danger of flooding. Russia has denied planning to blow up the dam and said Ukraine was firing missiles at it.
Neither side produced evidence to support their claims.
The dam may provide Russia with one of the few remaining routes across the Dnipro River – also known as Dnieper – in the partially occupied Kherson region.
Russia is evacuating civilians from the areas under its control, in expectation of a Ukrainian offensive to take the city.