Kyiv's forces have made gains on the front line in the southeast of the country, according to the Ukrainian military, a rare success as the slow-moving counteroffensive against well-defended Russian troops grinds on.

The breakthrough, if it holds, would be a vindication for Ukraine, which has endured growing criticism from some of its closest partners about the way it is managing the war.

Ukrainian soldiers had “achieved milestones” near several villages including Novoprokopivka and Verbove — both in Russian-controlled territory — military spokesman Andriy Kovalyov said in a Telegram post Wednesday.

“They were successful,” he said. “They are entrenched at the reached boundaries.”

Kovalyov did not elaborate on how much ground his country’s forces had taken, but video circulated online this week and geolocated by NBC News appeared to show Ukrainian forces fighting near Verbove, a village just over the front line.

U.S. defense officials told NBC News that while it’s true the Ukrainians had breached Russian defenses the advances are more of symbolic value than a big operational development. The breakthroughs are in a very small area and the Ukrainians have not moved personnel or vehicles through, they said.

The officials said that of the three lines of Russian defenses, the Ukrainians have pushed through the first line, which is mainly minefields and, in one place, they have punctured the second line, which is made of physical barriers like "dragon's teeth." They known face the third and toughest line of Russian defenses, which includes trenches.

Kovalyov's statement came after several open-source intelligence analysts said on social media that Ukrainian troops had breached Russian defensive lines in the area.

“Ukraine has breached the first Russian main defensive line, known as the Surovikin line, in the direction of Verbove,” Emil Kastehelmi wrote on X, formerly known as Twitter, adding that the village was “integrated to the Russian defenses.”