Ukrainian forces have made one of the most significant gains since the Russian invasion, capturing the Kremlin’s main military stronghold in the northwest of the country after making sweeping territorial advances in a surprise offensive.
The spectacular Russian frontline collapse on one of the main routes into the battleground of the Donbas came with the strategically vital city of Izium, which was surrounded by Ukrainian troops after they cut off a key supply line through Kupiansk to the north, towards Kharkiv.
