Negotiations from Russia and Ukraine came together for a second day of U.S.-mediated talks in Abu Dhabi on Saturday after an overnight wave of Russian attacks that knocked out power for millions of people in subzero winter cold.
The strikes by hundreds of Russian drones and missiles on Kyiv and Ukraine's second largest city Kharkiv prompted Foreign Minister Andrii Sybiha, who was not present at the talks, to accuse Russian President Vladimir Putin of acting "cynically".
"This barbaric attack once again proves that Putin's place is not at (U.S. President Donald Trump's) Board of Peace, but in the dock of the special tribunal," Sybiha wrote on X.
A source familiar with the situation told Reuters that the talks - which Ukrainian President Volodymyr Zelenskyy said were the first trilateral meetings under the U.S.-mediated peace process - had resumed on Saturday morning.
Kyiv is under mounting Trump administration pressure to make concessions to reach a peace deal in the war triggered by Russia's full-scale invasion in February 2022.
Zelenskyy had said on Friday that it was too early to draw conclusions from the first day of meetings in Abu Dhabi, and he had urged Russia to show it was ready to end the war. Senior representatives from Ukraine's armed forces and military intelligence were due to join the talks on Saturday.
Although U.S. peace envoy Steve Witkoff struck an upbeat tone at the annual World Economic Forum in Davos this week, saying that only one sticking point remained in the talks, Russian officials have sounded more skeptical.
Ahead of the discussions, Kremlin spokesman Dmitry Peskov said on Friday Russia had not dropped its insistence on Ukraine yielding all of its eastern area of Donbas, Ukraine's industrial heartland grouping the regions of Donetsk and Luhansk.
Putin's demand that Ukraine surrender the 20% it still holds of Donetsk - about 5,000 sq km (1,900 sq miles) - has proven a major stumbling block to any deal.
Zelenskyy refuses to give up land that Russia has not been able to capture in four years of grinding, attritional warfare. Polls show little appetite among Ukrainians for any territorial concessions.
Russia says it wants a diplomatic solution but will keep working to achieve its goals by military means as long as a negotiated solution remains elusive.
Rustem Umerov, the secretary of Ukraine's National Security and Defence Council and the head of its delegation, said in a statement late on Friday that the first day of talks had discussed parameters for ending the war and the "further logic of the negotiation process."
Ukraine's air force said Russia had launched 375 drones and 21 missiles in the overnight salvo, which once again targeted energy infrastructure, knocking out power and heat for large parts of Kyiv, the capital. At least one person was killed and 23 injured.
Before Saturday's bombardment, Kyiv had already endured two mass overnight attacks since the New Year that knocked out power and heating to hundreds of residential buildings. Ukraine's deputy prime minister said on Saturday that 800,000 people in Kyiv - where temperatures were around -10 Celsius - had been left without power after the latest Russian assault.
Zelenskyy said on Saturday that Russia's heavy overnight strikes showed that agreements on further air defence support made with Trump in Davos this week must be "fully implemented".
Both leaders described their talks on the sidelines of the Davos gathering of the world's political and business elite on Thursday as positive but declined to provide further details.
