There are widespread reports of Russian soldiers beating panicked retreats, of encircled units, and of large quantities of abandoned military hardware. The recapture of two logistical hubs, Izyum and Kupyansk, has in effect ended Russia’s grand plans to seize control of the entire Donbas, Ukraine’s eastern region. It also opens up the prospect of Ukraine regaining towns, like Severodonetsk, that Russia had clawed away only after months of bloody fighting. …

At one stage, Ukrainian units were moving so fast that senior officials were unsure how far they had got. Open-source analysts who track the conflict were forced to redraw their maps hourly. Serhiy Haidai, the governor of Ukraine’s Luhansk region, said he believed it would be only “a matter of time” before Ukrainian troops crossed the Donets river and moved into Svatove, Rubizhne, Lysychansk and Severodonetsk—towns in the northern part of the Luhansk region, which Russia boasted of capturing in its entirety in early July.

Russians and local collaborators were already “running”, he said. “Their lines are just disintegrating.” But Ukraine’s next moves would be “measured”, calculated to avoid losses, he promised. Oleh Zhdanov, a former operational officer at Ukraine’s general staff, said Ukraine’s military leadership would try to develop the attack at a slower pace. “We have to consolidate support lines to the rear. It’s dangerous to go too fast.”

There is some speculation whether Ukraine might now exploit Russian disarray to strike elsewhere: either by bolstering a counterattack in Kherson, where progress continues in piecemeal fashion, albeit with heavy casualties, or by opening up a third axis of attack somewhere else.