Meanwhile, Moscow has kept up its hammering of Ukraine's energy grid in overnight attacks that killed at least two people, according to Ukrainian officials.
More than 200,000 households in the Russian-held part of Ukraine's southern Zaporizhzhia region had no electricity on Sunday, according to the Kremlin-installed local governor.
In a Telegram post, Yevgeny Balitsky said nearly 400 settlements have had their supply cut, due to damage to power networks from Ukrainian drone strikes.
Russia has hammered Ukraine's power grid, especially in winter, throughout the almost four-year war. It aims to weaken Ukrainians' will to resist in a strategy that Kyiv officials call "weaponising winter."
Russia targeted energy infrastructure in Odesa region overnight on Sunday, according to Ukraine's Emergency Service. A fire broke out and was promptly extinguished.
At least six people were injured in the Dnipropetrovsk region because of Russian attacks, the emergency service said.
Ukrainian President Volodymyr Zelenskiy said in a Telegram post that repairing the country's energy system remains challenging, "but we are doing everything we can to restore everything as quickly as possible."
He said two people were killed in overnight attacks across the country that struck Sumy, Kharkiv, Dnipro Zaporizhzhia, Khmelnytskyi and Odesa.
In total over 1300 attack drones, 1050 guided aerial bombs and 29 missiles of various types were used by Russia to strike Ukraine this week, he added.
"If Russia deliberately delays the diplomatic process, the world's response should be decisive: more help for Ukraine and more pressure on the aggressor," Zelenskiy said.
He spoke the day after a Ukrainian delegation arrived in the United States for talks on a US-led diplomatic push to end the nearly four-year-old war.
On Friday, Zelenskiy said that the delegation would try to finalise with US officials documents for a proposed peace settlement that relate to postwar security guarantees and economic recovery.
If American officials approve the proposals, the US and Ukraine could sign the documents next week at the World Economic Forum in Davos, Switzerland, Zelenskyy said at a Kyiv news conference with Czech President Petr Pavel.
Trump plans to be in Davos, according to organisers.
Russia would still need to be consulted on the proposals.
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