Governor of Ukraine's Luhansk region said on Monday that all of the bridges to Sievierodonetsk were destroyed, adding that it is now impossible to bring cargoes into Sievierodonetsk or evacuate civilians.
The city, however, is not blockaded and there is still access to it, he added.
Governor Serhiy Gaidai wrote on the Telegram app that Russia had not taken full control of the city, and that "a part" of it remained under Ukrainian control, but that it was no longer possible to transport humanitarian cargoes there.
Gaidai also told RFE/RL's Ukrainian service that although 70% of the city was now controlled by Russia, the situation for Ukrainian troops there was "difficult but under control."
"They have the ability to send the wounded to hospitals, so there is still access," he said.
"It's hard to deliver weapons or reserves. Difficult, but not impossible," he added.
