Bakhmut on the Brink as Russian Forces 'Regain Momentum'—U.K. Intel

Russian forces have "regained some momentum" and advanced towards the center of Bakhmut, after months of clashes for control of the embattled eastern Ukrainian city, according to a new intelligence update.

Moscow's advance in and around the city "had largely stalled" since late March, the British defense ministry said on Friday.

Bakhmut has endured months of heavy fighting between Kyiv's and Moscow's forces, with both sides committed to controlling the decimated settlement. Battles in Bakhmut have racked up heavy casualty counts on both sides, with U.S. chairman of the Joint Chiefs of Staff, General Mark Milley, calling the battle for the city a "slaughter-fest" for Russian forces.

Russian military and mercenary forces have likely been joined by airborne troops, the British defense ministry said in a post to Twitter, adding that a key supply route for Ukraine to the west of Bakhmut is "likely severely threatened." They have likely reached the town center, controlling the west bank of the Bakhmutka River that runs through the settlement, the ministry wrote.

On Thursday, the Washington-based Institute for the Study of War think tank said Russian forces had continued with ground attacks in the city, making a "marginal advance in central Bakhmut." On Friday, the Ukrainian General Staff of the Armed Forces said Russia "continues to focus on offensive operations" in Bakhmut.

"Battles for Bakhmut continue," Andriy Yermak, the head of Ukrainian President Volodymyr Zelensky's office, said on Thursday. "They roam the streets, the enemy's attempts to surround the city fail," he wrote, reiterating Zelensky's previous label of the city as a "fortress."

But earlier this week, Zelensky suggested he could order a troop withdrawal, should Kyiv's forces become encircled by Moscow's fighters.

"The most important is not to lose our soldiers and of course if there is a moment of even hotter events and the danger we could lose our personnel because of encirclement—of course the corresponding correct decisions will be taken by generals there," Zelensky said, during a visit to Poland.

"But Ukrainian forces are "in Bakhmut and the enemy does not control it," Zelensky said.

Russian conventional troops have fought alongside mercenary forces in Bakhmut, with the paramilitary Wagner Group taking a prominent role in operations in and around the city.

But divisions between the Russian military and mercenary forces have been well-documented and very much in the public eye. Wagner Group chief Yevgeny Prigozhin previously accused the Russian Defense Ministry and military commanders of "treason" and of attempting to "destroy" the mercenary group.

However, there is a "realistic possibility" that Wagner and Russian military commanders in the area "have paused their ongoing feud and improved cooperation," the British defense ministry said on Friday.

Writing on Telegram on Thursday, Prigozhin said "clearly" Ukrainian forces were "not going anywhere." Only once Ukrainian fighters leave Bakhmut, he said, "we will completely expel everyone to the last."

Russia's flanks must be protected, as well as operating under a "well-organized command," he said. Crucially, he added, Moscow's troops need ammunition.

"When we solve all these three questions, then we can go anywhere," Prigozhin said.

On Tuesday, the British defense ministry said Russia was "likely seeking to sponsor and develop alternative" mercenary groups to replace the Wagner Group's combat role in Ukraine.

"However, no other known Russian PMC [private military company] currently approaches Wagner's size or combat power," the ministry added.

Newsweek has reached out to the Russian and Ukrainian defense ministries for comment via email.