MOSCOW/KYIV — The Kremlin on Monday said the US-brokered trilateral talks in the UAE between Russian and Ukrainian negotiators had been held in a "constructive spirit" but that there was still "significant work ahead".

"It would be a mistake to expect any significant results from the initial contacts … But the very fact that these contacts have begun in a constructive spirit can be viewed positively. However, there is significant work ahead," Kremlin spokesman Dmitry Peskov told journalists.

The two-day meeting in Abu Dhabi on Friday and Saturday was the first time negotiators from Moscow and Kyiv had faced each other to talk about a plan being pushed by US President Donald Trump to end the nearly four-year conflict.

The trilateral talks in the UAE will resume on Feb 1, according to a US official.

"I wouldn't say there was any friendliness there, it's hardly possible at this stage," Peskov said on Monday.

"But if you're trying to achieve something through negotiations, you need to speak constructively."

Ukrainian President Volodymyr Zelensky said on Sunday that a US document on security guarantees for Ukraine is completely ready and Kyiv is waiting for a time and place to sign it, indicating that weekend talks with Russia in Abu Dhabi made some progress.

"For us, security guarantees are first and foremost guarantees of security from the United States. The document is 100 percent ready, and we are waiting for our partners to confirm the date and place when we will sign it," Zelensky told a news conference during a visit to Vilnius, Lithuania's capital.

"The document will then be sent for ratification to the US Congress and the Ukrainian parliament," he said.

While diplomatic efforts to end the conflict have regained momentum, Moscow and Kyiv appear deadlocked over the issue of territory.

"These are two fundamentally different positions — Ukraine's and Russia's. The Americans are trying to find a compromise," Zelensky said, adding that all sides must be prepared to compromise.

A large-scale attack on Kyiv took place just as Ukrainian, Russian and US negotiators were discussing options in Abu Dhabi for ending the conflict.

More than 1,300 apartment buildings in the Ukrainian capital Kyiv were still without heating following a Russian missile and drone attack earlier this week, Kyiv Mayor Vitali Klitschko said on Sunday.

Russia launched a vast attack on Ukraine's energy system on Saturday, rocking Kyiv with explosions overnight and leaving 1.2 million properties without power nationwide during sub-zero winter temperatures.

"Russia's main targets right now are our energy sector, critical infrastructure, and residential buildings," Zelensky said on X.

In the Russian city of Slavyanskon-Kuban in the country's Krasnodar region, two enterprises caught fire and one person was injured ?in the city after drone fragments fell on them, the regional emergencies center said on Monday.

The center did not specify which enterprises were affected. The city hosts a private refinery with a capacity of around 100,000 barrels per day, supplying fuel for both domestic use and export.

Russia's defense ministry said air defense systems had intercepted and destroyed 40 Ukrainian drones overnight, including 34 in the Krasnodar region.

AGENCIES VIA XINHUA