U.K. intel officials: Russia forces making ‘modest’ gains in Ukraine, boost use of cluster bombs

Russian forces in Ukraine have moved the front line more than a mile since October in a pincer movement intended to surround the critical town of Avdiivka in the disputed Donbas region, British officials said this week.

Although considered a relatively modest advance, it still amounts to one of the largest Russian gains of Ukrainian territory since the spring of 2023. The advance has come at a high cost for Moscow, however. In their latest assessment of the battlefield in Ukraine, U.K. military intelligence officials on Monday said Russia has taken thousands of casualties in the drive.

The operation is gradually bringing Russian troops closer to the Avdiivka Coke and Chemical plant, where Ukrainian forces maintain one of their main defensive positions, U.K. officials said.

“Although Avdiivka has become a salient or bulge in the Ukrainian front line, Ukraine remains in control of a corridor of territory approximately [4.5 miles] wide, through which it continues to supply the town,” British officials said on social media.

With winter fast approaching, Russian forces have also begun to more aggressively employ the RBK-500, their latest cluster munition bomb, on the battlefield. Depending on the variant, each round will eject up to 350 submunitions which in turn detonates with hundreds of high-velocity fragments or a single, larger anti-tank charge, British intelligence officials said Tuesday.

Russian RBK-500 rounds are reported to have been used against Ukrainian forces near Avdiivka and in Vuhledar, another city in the Donbas region. They have also used glide bombs launched well behind the front lines to deploy the cluster bombs, despite the “poor accuracy” of the delivery systems.

A single RBK-500 can cause damage over an area of several hundred meters, increasing the chance of inflicting at least some damage on the intended target, U.K. officials said.