Ukrainian President Volodymyr Zelenskyy visited the eastern city of Bakhmut, the scene of some of the most intense combat since Russia invaded the country.

He met troops on Tuesday and praised their “courage, resilience and strength” as artillery boomed in the background.

Russian President Vladimir Putin also hailed the “courage and self-denial” of his forces in Ukraine, but he did so at a ceremony in an opulent and glittering hall at the Kremlin.

Both leaders sought to build morale as the stalemated conflict grinds through its 10th month and winter sets in.

“Since May, the occupiers have been trying to break our Bakhmut, but time goes by and Bakhmut is already breaking not only the Russian army, but also the Russian mercenaries who came to replace the wasted army of the occupiers,” Zelenskyy said.

Russia’s invasion, which began on February 24, has lost momentum in recent months. The annexed provinces of Donetsk, Kherson, Luhansk and Zaporizhia remain fiercely contested. Capturing Bakhmut would sever Ukraine’s supply lines and open a route for Russian forces to press on towards cities that are key Ukrainian strongholds in the province.

At the Kremlin ceremony, on a holiday honouring Russia’s military and security agencies, Putin presented awards to the Moscow-appointed heads of four regions of Ukraine that Russia illegally annexed in September.

“Our country has often faced challenges and defended its sovereignty,” Putin said. “Now, Russia is again facing such challenge. Soldiers, officers and volunteers are showing outstanding examples of courage and self-denial on the front line.”

He promised to reinforce units there with more equipment and personnel. The regions are under pressure from a Ukrainian counteroffensive.

Putin also called on counterintelligence officers to step up efforts to “derail activities by foreign spy agencies and quickly track down traitors, spies and saboteurs”.

Russia now controls about 18 percent of internationally recognised areas of Ukraine, including those parts of the Donbas and Crimea seized earlier, it said.

With the fighting in the east at a deadlock, Moscow has used missiles and drones to attack Ukraine’s power, hoping to leave locals without electricity as freezing winter weather sets in.

Life in the Ukrainian capital took a minor but welcomed step towards normality with the reopening of two of Kyiv’s main subway stations for the first time since the start of the war. The key hubs of Maidan Nezalezhnosti and Khreschatyk, like the capital’s other underground stations, have served as shelters during Russian air raids.

“It’s the feeling that despite everything, we are returning to a routine that we were used to,” said 24-year-old passenger Denys Kapustin. “This is very important, very important.”