Jan 21 (Reuters) - A fire broke out at a terminal of Russia's largest liquefied natural gas producer Novatek on the Baltic Sea, the governor of the Leningrad region said early on Sunday, amid reports of drone sightings in the area.

"There were no casualties as a result of the fire at the Novatek terminal in the port of Ust-Luga. The personnel were evacuated," Alexander Drozdenko said on the Telegram messaging app.

Drozdenko did not say what caused the fire at the Novatek terminal at the all-season port in the Russian part of the Gulf of Finland, about 170 km (110 miles) west of St. Petersburg and 35 km from the Estonian border.

Russian news outlet Shot reported on Telegram that residents in the area had heard a drone followed by several explosions.

St. Petersburg-based news outlet Fontanka said at least two drones were spotted in the sky flying towards St. Petersburg before the reports of the fire at the terminal.

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

Reuters could not independently verify the reports.

Russia and Ukraine have targeted each other's energy infrastructure in strikes designed to disrupt supply lines and logistics and to demoralise the other side in a nearly two-year 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 Ukraine. That followed a Thursday attack on a Russian Baltic Sea oil terminal that Russian officials said was unsuccessful.

Drozdenko said a "high alert regime" had been introduced in the area and officials had gathered for an emergency meeting. (Reporting by Lidia Kelly in Melbourne; Editing by William Mallard)