Live news: Advancing Russian forces reach key highway out of Donbas cities

Live news updates: Advancing Russian forces came closer to surrounding Ukrainian troops in the east, briefly seizing positions on the last highway out of a crucial pair of Ukrainian-held cities before being beaten back, a Ukrainian official said on Thursday.

Russia has poured thousands of troops into its assault in the eastern Donbas region, attacking from three sides in an attempt to encircle Ukrainian forces in Sievierodonetsk and Lysychansk. The cities' fall would bring nearly the whole of Luhansk province under Russian control, a key Kremlin war aim.

Serhiy Gaidai, governor of Luhansk province, acknowledged that Ukrainian forces were retreating, but said the last road out of Lysychansk and Sievierodonetsk, which straddle the Siversky Donets river, remained outside Russian control.