At least 14 people were killed in Poltava, Ukrainian officials said, blaming Russia. Four died in Sudzha, a Russian town held by Ukraine, in a strike each country blamed on the other.

The mayor, Vitali Klitschko, who has had a tense relationship with President Volodymyr Zelensky, accused him of trying to usurp the powers of elected officials in the capital.

President Trump jabs at the Russian leader with threats; Vladimir Putin responds with flattery. But there are notable signals in their jousting, including a revived discussion about nuclear arms control.

Russia says Ukraine shot down a military transport carrying 65 captured Ukrainians. Ukraine has not confirmed its role, identified the bodies it received, or said how it happened.

President Trump doubled down on the prospect of across-the-board tariffs in a video appearance to business executives and politicians gathered in Davos, Switzerland.

The high popularity that the Ukrainian president had in the early days of the Russian invasion, with an approval rating of about 90 percent, has dipped badly.

The development of a new generation of drones has revolutionized how wars are fought, according to U.S. officials.

Prime Minister Keir Starmer signaled continued solidarity, with further U.S. support in question under a second Trump administration.

Ukrainian soldiers are describing fierce clashes as Russian forces try to retake territory in the Kursk region that could be key in eventual cease-fire talks.

Ukraine’s president released a video of the two soldiers being interrogated, revealing they knew little about the war they were sent to fight in.

President Volodymyr Zelensky said the soldiers were captured in the western Kursk region, where Ukraine has been fighting to hold on to territory it seized last summer.

In an impassioned address to officials from countries supporting Ukraine, Mr. Zelensky said “a new chapter” would be starting for Europe and the rest of the world, requiring even more cooperation.

Moscow again struck Ukraine’s energy infrastructure, part of an effort to wear down the country. “In the trenches, there are no holidays,” one man said.

North Korean troops have now entered Russia’s war with Ukraine in a major way, and some have been killed, Western officials say.