Ukraine's Forces Have Penetrated Russian Front Lines in Some Areas: U.K.

"Significant" Ukrainian military operations have taken place in eastern and southern Ukraine, British defense officials have said, amid reports that Kyiv's long-awaited counteroffensive had begun.

In its daily update, the U.K. Ministry of Defense said Ukrainian troops "have likely made good progress" and managed to penetrate the first line of Russian defenses in some areas, although in other sectors, Kyiv's advance "has been slower."

Meanwhile, Russia's performance has been "mixed" and while some units were likely conducting credible maneuver defense operations, other units have pulled back in "some disorder," it said.

There are also increased reports of Russian casualties "as they withdraw through their own minefields," it added. Saturday's update also said that Russia's air force had been "unusually active" over the south of Ukraine where Moscow can use the airspace more easily than in other parts of the country.

"However, it remains unclear whether tactical airstrikes have been effective," added the U.K. ministry's update which emphasizes Russian losses and Ukrainian gains. Newsweek has contacted the Russian Defense Ministry for comment.

A separate assessment by the Institute for the Study of War (ISW) said on Friday that Kyiv's forces were continuing counteroffensive operations in at least four areas of the front.

These included "tactical gains" in the west of Donetsk Oblast near the Donetsk-Zaporizhzhia Oblast border and ground attacks in western Zaporizhzhia Oblast in which a Russian source suggested that Ukrainian forces made "incremental gains."

The Russian Ministry of Defense (MoD) has said its forces had repelled limited and localized Ukrainian ground attacks in the Kreminna area.

Meanwhile, Russian President Vladimir Putin said the Ukrainian counteroffensive had been ongoing for five days but "did not reach their aims in any area of combat" after committing "strategic reserves.

Putin said Ukrainian forces had suffered significant losses which he put down to superior Russian military equipment and personnel. "Putin's discussion of the Ukrainian counteroffensive is a notable departure from his previous distanced approach to discussing battlefield realities," the ISW said.

This may show that the Kremlin "is learning from its previous failed approach to rhetorically downplay successful Ukrainian counteroffensives in 2022," the think tank added.

Former British military intelligence officer Philip Ingram said that Ukrainian forces had launched their counteroffensive on multiple axes across the front line with a significant push around Bakhmut with the aim of keeping the Russians fixed there.

There would likely be a main effort further south in the Zaporizhzhia region, "possibly heading for Orikhiv and then probably Tomak as they try to cut the land bridge between Crimea and the Donbas," he told Newsweek.

"In some areas, Russian defense has collapsed but along the main effort route it is clear Russian defences have been well prepared—Ukrainian losses reported on Russian channels are light compared to what I would expect," he said.

He believed that if unconfirmed reports of Russians having to commit reserve forces were true "then the Ukrainians are making significant inroads to Russian defenses."

However, Ingram added that attacking Russia's well-prepared defenses would be "very hard and very costly in manpower and equipment. It is too early to assess what the reality is on the ground especially with the paucity of verifiable information."