Russian energy company Novatek (NVTK.MM) said on Sunday it had been forced to suspend some operations at a huge Baltic Sea fuel export terminal due to a fire started by what Ukrainian media said was a drone attack.

The giant Ust-Luga complex, located on the Gulf of Finland about 170 km (110 miles) west of St. Petersburg, is used to ship oil and gas products to international markets. It processes stable gas condensate - a type of light oil - into light and heavy naphtha, kerosene and diesel to be shipped by sea.

It was not clear how long the disruption would last, how many tankers would have to idle outside the port, and what the knock-on effect would be on international energy markets.