Ukraine, Russia and the United States will start a second day of talks in Abu Dhabi on Thursday, seeking to end Moscow's nearly four-year invasion.
The US-mediated talks are the latest chapter in the so far unsuccessful diplomatic effort to halt the war triggered by Russia's full-scale offensive in February 2022.
A first day of trilateral talks in the Emirati capital on Wednesday concluded with Kyiv describing the negotiations as "substantive and productive", though there was no apparent breakthrough.
The conflict is Europe's deadliest since World War II, with hundreds of thousands killed, millions forced to flee their homes and much of eastern and southern Ukraine left decimated.
Underscoring the human toll, Ukrainian President Volodymyr Zelensky said on Wednesday that 55,000 of his country's troops had been killed, a rare assessment of battlefield losses by either side.
Russia has also stepped up strikes on Ukraine's power infrastructure, leaving many people, including residents of the capital Kyiv, without power and shivering through temperatures as low as minus 20C in recent days.
Ukraine's top negotiator Rustem Umerov said "concrete steps and practical solutions" had been discussed during the first day of the talks.
But the Kremlin repeated its hardline demand that Kyiv must give in, with spokesman Dmitry Peskov telling reporters the fighting would persist "until the Kyiv regime makes the appropriate decisions".
The main sticking point in the negotiations is the long-term fate of territory in eastern Ukraine.
Moscow is demanding that Kyiv pull its troops out of swathes of the Donbas, including heavily fortified cities atop vast natural resources, as a precondition of any deal.
It also wants international recognition that land seized in the invasion belongs to Russia.
Kyiv has said the conflict should be frozen along the current front line and has rejected a pull-back of forces.
Trilateral negotiations, which were first held January 23 and 24 in Abu Dhabi, are the most public sign of progress so far in US President Donald Trump's push to negotiate an end to the war.
His envoy Steve Witkoff and son-in-law Jared Kushner have been sent to try to corral the sides into an agreement.
In Ukraine, foreign ministry spokesman Georgiy Tykhy said of the second round of talks that Kyiv was "interested in finding out what the Russians and Americans really want".
Putin 'only scared of Trump'
Zelensky said the US president's role would be crucial, telling French television in an interview broadcast Wednesday that "Putin is only scared of Trump".
Trump could use economic sanctions against Russia or transfer weapons to Ukraine to "maintain this pressure on Putin", Zelensky said, but added that Kyiv would not compromise on sovereignty.
Russia occupies around 20 percent of Ukraine. It claims the Lugansk, Kherson and Zaporizhzhia regions as its own, and holds pockets of territory in at least three other Ukrainian regions in the east.
Kyiv still controls around one-fifth of the Donetsk region. It has warned that ceding ground will embolden Moscow, and that it will not sign a deal that fails to deter Russia from invading again.
