Ukraine's state hydropower company said a Russian strike hit Ukraine's largest dam, the DniproHES in Zaporizhzhia, in southeastern Ukraine. Officials said there was no risk of a breach.
A power line to the Zaporizhzhia nuclear power plant was also cut following a missile attack, the plant's management said on Telegram. But power supply to the plant was guaranteed by a replacement line and there was no safety risk, it added.
Ukraine's Energy Minister Herman Halushchenko said Ukraine had suffered what was "the largest attack" on its energy infrastructure in its recent past.
"The goal is not just to damage, but to try again, like last year, to cause a large-scale failure of the country's energy system," he wrote on Facebook.
Authorities in Kharkiv, in Ukraine's northeast, said Russia targeted energy facilities with 15 strikes.
"The city is almost completely without electricity," Kharkiv regional Governor Oleh Syniehubov wrote on Telegram.
Ukraine's power grid operator said there were emergency blackouts in seven regions across the country.
Ukraine says 2 killed in Russian attacks
Ukraine's Interior Minister said two people were killed and 14 injured in the overnight Russian attacks on Ukraine.
Six people were injured in Zaporizhzhia, where Ukraine's largest dam was hit, and another eight where injured in Khmelnytskyi, in western Ukraine, the ministry said.
Three people at the sites of the attacks remain missing, it added.
Zelenskyy: Russia launched 90 missiles, 60 drones
Ukrainian President Volodymyr Zelenskyy said that Russia launched a massive wave of overnight attacks overnight, with 90 missiles and 60 Iranian-made Shahed drones.
"The world sees the targets of Russian terrorists as clearly as possible: power plants and energy supply lines, a hydroelectric dam, ordinary residential buildings, even a trolleybus."
Zelenskyy said that the rescue efforts were underway and electricity was being restored attacks on energy infrastructure caused after power cuts.
The Ukrainian president called for support from Kyiv's allies, saying that "Russian missiles have no delays, unlike aid packages for Ukraine."
"It is critical to understand the cost of delays and postponed decisions [...] Our partners know exactly what is needed."
China says talks need to involve both Ukraine and Russia
China's attempts to position itself as a mediator in the Ukraine conflict seemed to have ended without success after its Eurasia envoy Li Hui cited a "significant gap" between Kyiv and Moscow regarding peace talks.
Despite the "bumpy road ahead," he said, "at the end they all agree that the war must be resolved through negotiations rather than guns." He added that all parties "recognize the danger of the current situation continuing to deteriorate."
Li said both parties agreed with Beijing's calls for cooling down the situation, adding that they expected his country "to play a more constructive role."
The Chinese diplomat also said that Moscow expressed appreciation for China's round of global diplomacy, adding that Russia believes "the crisis ultimately needs to be resolved through negotiation."
China's attempts to mediate the conflict have often been met with skepticism, given Beijing's close ties with Moscow. The country has consistently steered clear of condemning Russia for its invasion of Ukraine.
EU looking into funding Ukraine weapons with frozen Russian assets
A summit of European Union leaders in Brussels is due to convene for a second day on Friday.
On the first day of the summit, EU leaders agreed on several statements condemning Russia and pledging continued support for Ukraine.
"The European Council is ever more steadfast in its support for Ukraine's independence, sovereignty, and territorial integrity within its internationally recognized border. Russia must not prevail," the agreed-upon conclusions of the leaders' summit said.
"Given the urgency of the situation, the European Union is determined to continue providing Ukraine and its people all the necessary political, financial, economic, humanitarian, and diplomatic support for as long as it takes and as intensely as needed," it added.
They also said they would look into the next steps necessary to use revenues from frozen Russian assets in the EU to fund military support for Ukraine.
Ukraine says 15 blasts hit Kharkiv
Some 15 blasts were heard in Ukraine's northeastern Kharkiv on Friday morning, a Ukrainian official said, suggesting the missile strikes targeted the city's power supply.
Kharkiv Mayor Ihor Terekhov reported partial blackouts due to what he said were Russian strikes. Some of the city's water pumps also stopped, he added, though no casualties were reported.
"I urge everyone to be careful - the enemy may continue shelling," Terekhov said in a statement on the Telegram messaging platform.