The first three-way peace talks between Russia, Ukraine, and the US have ended in Abu Dhabi with no apparent breakthrough, as fighting rages.
Ukrainian President Volodymyr Zelensky raised the possibility of a second meeting as early as next week, while an American official said a new round would begin on 1 February.
The two-day talks ended after waves of Russian air strikes targeted Ukraine's badly damaged energy infrastructure, killing one person and injuring 35 others, Ukrainian officials said.
Russia accused Ukraine of attacking an ambulance in Ukrainian territory under its control, killing three medics. Later, it reported a Ukrainian missile attack on energy infrastructure in Belgorod.
The BBC could not independently verify the reports.
The talks in Abu Dhabi were the first trilateral meeting since the Kremlin launched its full-scale invasion of its neighbour in 2022.
The central focus of the discussions was the possible parameters for ending the war, Zelensky posted on X.
I highly value the understanding of the need for American monitoring and oversight of the process of ending the war and ensuring genuine security.
All sides had agreed to report back to their capitals and coordinate further steps with their leaders, he added.
We've agreed that the next round begins next Sunday in Abu Dhabi again, an unnamed US official told reporters.
The decision to hold further talks was a good sign and a lot of work had been done over the two days of negotiations, the official added.
The Russian state news agency Ria-Novosti reported that Moscow remained open to a continuation of dialogue with Ukraine and the US.
Vitali Klitschko, mayor of the Ukrainian capital Kyiv, said one person had died and four had been wounded by Russian air strikes on Friday night, while the mayor of the city of Kharkiv reported that 31 people had been hurt there.
Kyiv's critical infrastructure was damaged, Klitschko said, leaving 6,000 buildings without heating.
Temperatures have fallen to around -12C in parts of Ukraine. Zelensky said for his part that the main target of the Russians had been the energy infrastructure.
Ukrainian Foreign Minister Andrii Sybiha said the brutal Russian attack - cynically ordered by President Vladimir Putin - had hit not only our people, but also the negotiation table.
Meanwhile, Russia accused Ukraine of a barbaric crime against the civilian population of Kherson region, which is partially under Russian control.
Russian foreign ministry spokesperson Maria Zakharova said a clearly marked ambulance carrying a medical team had been attacked by a Ukrainian drone.
Despite the challenges, President Zelensky emphasized the need for continued dialogue, characterizing the negotiations as essential in the quest for peace.
