Nasa’s satellite resource FIRMS, used to detect heat signatures on the Earth’s surface, indicates Primorsk was still burning as of 02:54 BST on Monday.
A heat signature was also detected by FIRMS at Ust-Luga at 12:28 on Monday. Leningrad region’s governor, Alexander Drozdenko, had said the fire had been contained on Sunday. He did not report any casualties.
BBC Verify has also confirmed several videos showing the aftermath of attacks on all three facilities in the past week, including clips showing massive smoke plumes rising into the sky from Primorsk.
The commander of Ukrainian military drone forces, Robert Brovdi, has said that an operation targeting these three Baltic oil export facilities was carried out between 23 and 28 March.
Brovdi added the strikes were aimed at “demilitarising Russia’s oil arteries, refining capacity and crude export infrastructure”.
Ukraine’s military has said the Kirishi refinery is among the three largest oil‑processing plants in Russia, including the production of “fuels that support the armed forces of the aggressor state”.