(NewsNation) — Ukrainian forces on Friday claimed new success in their counteroffensive against Russian forces in the country’s east.

“These weren’t exactly heavily manned positions by the Russians. But it certainly caught the Russians off guard and shows how the Ukrainians are able to go on the offensive,” said NewsNation’s Leland Vittert.

Ukraine’s military said it also launched new attacks on Russian pontoon bridges used to bring supplies across the Dnieper River to Kherson, one of the largest Russian-occupied cities, and the adjacent region. 

“The Ukrainians are now pushing here into Kherson and stopping the Russians from any ability to advance,” Vittert said.

The United States’ top diplomat and the head of NATO noted the advances but cautioned that the war is likely to drag on for months.

“The one thing that they’ve not been able to do is cut off the Ukrainians from the Black Sea,” Vittert noted.

Watch Leland Vittert‘s full report in the video player at the top of the page.

The Associated Press contributed to this report.