Ukraine remains in control of the Azot chemical plant in Sievierodonetsk where hundreds of civilians are sheltering, the region's governor said on Saturday.

"The information about the blockade of the Azot plant is a lie," Serhiy Gaidai, governor of the Luhansk region partially controlled by pro-Russian forces, said on Telegram.

Ukraine has said some 800 people were hiding in several bomb shelters underneath the Azot plant, including about 200 employees and 600 residents.