The Ukrainian military claimed on Sunday that it downed five Russian fighter jets over the last three days—a potentially major success for the country, if accurate, amid an unproductive winter in its war with Russia.

Those recent Ukrainian successes, in fact, were already tempered by Russia’s own claim—that it had taken the eastern Ukrainian city of Marinka.

Russian Defense Minister Sergei Shoigu said in a televised meeting Monday that its forces had “completely liberated the settlement of Maryinka today.” But as with most things in Ukraine, it wasn’t immediately clear whether Russia was being completely truthful. A spokesman for the Ukrainian military denied that Maryinka was in Russian hands, with the spokesman saying Ukrainian forces were still inside the city.

In a Facebook post Sunday, the Ukrainian military claimed it had destroyed two Russian fighter jets. The claim came just days after the military said it downed three other Russian fighters in the southern region of the country.

In a Dec. 25 post on Telegram, Ukrainian President Volodymyr Zelensky said this Christmas “sets the right mood for the whole coming year—the mood of our possibilities.”

“The stronger our air defense system is, the fewer Russian devils there will be in our sky and on our land,” he said.

Russia has yet to comment on the claims, but a Telegram channel run by Russian Army Capt. Ilya Tumanov—according to The New York Times—reported Friday that a number of its planes were lost. The Telegram account said those planes were downed by Patriot missiles, an air-defense system designed by the United States.

Russia's Defence Ministry also said Sunday that it had shot down four Ukrainian military aircraft in the Southern region over the weekend, according to Reuters.

The next day, Shoigu told Russian president Vladimir Putin in the televised meeting that Russian forces had completely captured Marinka, a Ukrainian city that has been reduced to rubble over the course of the war.

Ukrainian military spokesperson Oleksandr Shtupun pushed back, calling Shoigu’s claims “incorrect," and saying in televised remarks that Ukrainian forces are “in the administrative borders of Marinka.” The military also said in its Facebook post Sunday that its forces “continue to restrain the enemy in the areas of Marinka.”

The news comes as Ukraine struggles to make progress and its Western allies face pressure to cut back on aid in the now nearly two-year-long war. The U.K. Ministry of Defense said last week that, after a failed summer counteroffensive, Ukraine had moved to a more defensive stance.

Still, Zelensky ended his Christmas dispatch on a positive note. “Merry Christmas, dear Ukrainians! Let this bright time make the whole next year brighter for us,” he said.