A fire broke out at a Baltic Sea terminal belonging to Novatek, Russia's largest liquefied natural gas producer, after a suspected Ukrainian drone attack, forcing the company to suspend some operations there.

The Ust-Luga complex, located on the Gulf of Finland about 170 km (110 miles) west of St. Petersburg, processes stable gas condensate into light and heavy naphtha, jet fuel, fuel oil and gasoil, according to Novatek's website. The port is used to ship processed products to international markets.

The Interfax-Ukraine news agency, citing unnamed sources, said the fire was the result of a special operation carried out by Ukraine's security services.

"The Ust-Luga Oil terminal in the Leningrad region is an important facility for the enemy. Fuel is refined there, which, among other things, is also supplied to Russian troops," it cited one source as saying.

"A successful attack on such a terminal not only causes economic damage to the enemy, depriving the occupiers of the opportunity to earn money to wage war in Ukraine, but also significantly complicates the logistics of fuel for the Russian military."

Reuters could not confirm that the fire resulted from a Ukrainian drone attack.

Alexander Drozdenko, the Leningrad region's governor, said on the Telegram messaging app, that there had been no casualties and that all workers had been safely evacuated.

Russian news agencies reported that two storage tanks and a pumping station had been damaged, but that the fire had now been brought under control.

Novatek said in a statement it had suspended some operations after the fire which it said was the result of "external influence."

"The technological process at Novatek-Ust-Luga has been stopped, and an operational headquarters has been established to eliminate the consequences. Damage assessment will be carried out later," the company said.

Russian news outlet Shot reported that local residents had heard a drone operating nearby followed by several explosions.

Russia and Ukraine have targeted each other's energy infrastructure in strikes designed to disrupt supply lines and logistics, each side seeking to demoralise the other in a nearly two-year-old war that shows no sign of ending.

On Friday, a drone attack hit an oil depot in Russia's western region of Bryansk, bordering Ukraine, for which Moscow blamed Kyiv. That came a day after an attack on a Russian Baltic Sea oil terminal that Russian officials said was unsuccessful.

Baza, a Russian news outlet known for its security services contacts, posted footage on Telegram of large flames shooting into the sky over what appeared to be an industrial complex.

Three international tanker ships were anchored near the fire, though there were no reports of damage to them, the Fontanka outlet said.

Drozdenko said a "high alert regime" had been introduced and that officials had gathered for an emergency meeting.

Novatek processed 3.4 million tons of stable gas condensate at the complex in the first half of 2023, according to the most recent data available, up 0.6% from the same period a year earlier. (Reuters)