The head of the Russian mercenary Wagner Group said Thursday that his forces can take notes from Ukrainian troops amid the ongoing war.

Yevgeny Prigozhin’s Wagner forces have been involved in the high-profile fights for the Ukrainian cities of Bakhmut and Soledar in the eastern Donetsk region.

Russia recently claimed to have captured Soledar, a small salt-mining town several miles from Bakhmut, and the U.K. Defence Ministry wrote in an intelligence update on Wednesday that Ukrainian forces had “likely withdrawn” from the town by the end of January 16.

But Russian and Wagner troops have yet to capture Bakhmut after months of fighting that Ukrainian President Volodymyr Zelensky said last month had left the city “destroyed.”

Prigozhin acknowledged the performance of Ukrainian troops in the Bakhmut battle in a statement published by his press service on Thursday, according to the Kyiv Post.

“The Ukrainian army is working clearly and harmoniously. We have a lot to learn from them,” Prigozhin said. He added that Bakhmut “will be captured.”

Prigozhin Compliments Ukraine Fighters
A Ukrainian soldier stands guard in a liberated town previously occupied by Russian forces on January 13 in Buhaivka, Ukraine. In inset, Yevgeny Prigozhin attends a meeting with foreign investors at Konstantin Palace on June 16, 2016, in Saint Petersburg, Russia. Prigozhin said Thursday that his Wagner Group forces can take some notes from Ukrainian troops amid the ongoing war.
Pierre Crom/Getty Images; Mikhail Svetlov/Getty Images

Any admissions from Russian President Vladimir Putin that his war in Ukraine has not been going completely to plan have been rare. Last month, Putin acknowledged that the situation in Ukraine’s Donetsk, Luhansk, Kherson and Zaporizhzhia regions—all four of which were declared as annexed by Russia last year despite international outcry—was “extremely difficult,” Insider reported.

But earlier this week, Putin insisted during an interview that his “special military operation” in Ukraine was still going to plan.

“The dynamics are positive,” Putin said during the interview. “Everything is developing within the plan of the Defense Ministry and the General Staff. And I hope that our fighters will please us more than once again with the results of their combat work.”

Catholic University of America history professor Michael Kimmage said that the acknowledgment from Prigozhin, a Putin ally, of the Ukrainian army’s performance is notable.

Kimmage told Newsweek that “for anybody in the Kremlin inner circle to pay these kinds of compliments” to the Ukrainian army “is unusual.” He said that while it requires some reading between the lines, Prigozhin’s comments do seem to be an admission that “things are not going well” for Russia.

Prigozhin made another rare comment in an interview earlier this month about the difficulties his Wagner forces have encountered in the fight for Bakhmut. He told the Russian state media outlet Ria Novosti that there is a “fortress in every house” in Bakhmut, and the fight to take each house can sometimes last for more than a day or even for weeks.

Once each “fortress” has been captured, another is already in place behind it, Prigozhin said.

“And how many such lines of defense are there in [Bakhmut]? If we say 500, we probably won’t be mistaken,” he added.

Newsweek reached out to Ukraine’s Ministry of Defence for comment.