The Kremlin has threatened to walk out of peace talks after accusing Ukrainian helicopters of attacking an oil facility inside Russia.
As day broke in Belgorod, the oil facility was ablaze, with the fire allegedly sparked by Ukrainian missiles.
The oil facility is only 25 miles from the border with Ukraine, and was ablaze on Friday morning.
Firefighters try to tackle the huge blaze at the oil depot this morning as plumes of black smoke billow from the site.
Ukrainian journalist Yuriy Butusov claimed that the depot was destroyed by an OTR-21 Tochka-U ballistic missile fired by the Ukrainian 19th missile brigade, but his report was not confirmed by Ukrainian officials.
Photos on social media appeared to show the oil facility in Belgorod ablaze in the early hours of Friday.
Russian forces struck a Red Cross facility in Mariupol but no staff were inside after it was evacuated. »