Ukraine has imposed emergency power shutdowns across most of the country, a day after Russia unleashed large-scale attacks on energy infrastructure.
The shutdowns were in place in all but three regions following Saturday's drone and missile attack on energy targets that injured at least 19 people.
Ukraine's state-owned power grid operator Ukrenergo said the shutdowns affected both industrial and household consumers.
Russian attacks on Ukraine's power grid in recent weeks have forced the government to institute nationwide rolling blackouts.
Without adequate air defences to counter such assaults and allow for repairs, the shortages could worsen as need spikes in late summer and the bitter-cold winter.
Among the most significant recent strikes were an April barrage that damaged Kyiv's largest thermal power plant and a massive attack on May 8 that targeted power generation and transmission facilities in several regions.
Following Saturday's strike, Ukraine's air force said on Sunday that air defences had shot down all 25 drones launched overnight.
Meanwhile, Russia claimed on Sunday that it had taken control of the village of Umanske in the partially Russian-occupied Donetsk region.
Russia’s new offensive in the north has centred on the Kharkiv region, but seems to include testing Ukrainian defences in Donetsk farther south, while also launching incursions in the northern Sumy and Chernihiv regions.
In Russia, six people were injured in shelling in the city of Shebekino in the Belgorod region bordering Ukraine, the regional governor Vyacheslav Gladkov said Sunday.
Speaking at the Shangri-La security conference in Singapore, Ukrainian President Volodymyr Zelenskyy accused China of helping Russia to undermine an upcoming international peace summit due to take place later this month in Switzerland.
"Russia, using Chinese influence in the region, using Chinese diplomats also, does everything to disrupt the peace summit," he said, "This is unfortunate that such a big, independent, powerful country as China is an instrument in the hands of Putin."
Zelenskyy said more than 100 countries had confirmed they would participate in the summit which takes place at a resort above Lake Lucerne in central Switzerland from June 15.
Also on Sunday, White House National Security Adviser John Kirby confirmed President Joe Biden had agreed to allow Ukraine to use some US-provided weapons to strike inside Russia to relieve the "incredible downward pressure" that Russia has put on Kharkiv.
