A Rosneft-owned refinery in Ukraine has been hit by shelling, causing an oil reservoir to go up in flames, according to a report.
Two warehouses at the facility in the east of the restive country, believed to be the Lisichansk refinery, were also destroyed by the shelling on Friday, Reuters reported.
The refinery in the Luhansk region has not, however, been operating since March 2012, the news wire said.
Nobody was available for comment at Rosneft on Friday.
The Moscow-based oil behemoth had earlier on Friday responded to the imposition by the US Treasury Department earlier this week of sanctions against it in relation to the ongoing feud between Russia and Ukraine.
Luhansk is near where a Malaysian Airlines Boeing 777, flight MH17, crashed on Thursday, reportedly after being shot down.
All 298 people on board were killed, with Shell confirming on Friday that some of its employees were among the dead.