Russian forces trying to take Kyiv appear to have repositioned to cut the Ukrainian capital off on all sides and reduce their own risk of being hit by the defending troops.

“Elements of the large Russian column north of Kyiv have dispersed. This is likely to support a Russian attempt to encircle the city,” the British ministry said in a daily assessment of Russia’s assault on Ukraine.

Commercial-satellite imagery in recent days showed that a large Russian military convoy last seen northwest of Kyiv had largely dispersed. The U.K. on Friday said Russian troops appeared to be regrouping for a fresh assault.

The dispersal of the attacking troops “could also be an attempt by Russia to reduce its vulnerability to Ukrainian counterattacks, which have taken a significant toll on Russian forces,” the British ministry said Saturday.

The bulk of Russian ground forces now have made it to around 15 miles from the city center, according to the U.K.