Over 2,000 civilians were evacuated Wednesday after a fire broke out at a military training field in annexed Crimea, the Russian-backed governor of the region said.

Authorities did not specify the cause of the blaze, but some Russian media reported that detonations were heard in the area and footage showed columns of black smoke in the sky.

The news comes days after Ukraine used waterborne drones to attack the Kerch bridge, a key military supply artery from mainland Russia to the annexed Crimea.

"The temporary evacuation of residents of four localities adjacent to the military field in the Kirovsky district is planned. That's more than 2,000 people," said the Moscow-installed head of Crimea, Sergei Aksyonov.

A section of the Tavrida highway that crosses the peninsula had been closed due to the fire.

Authorities were carrying out the "temporary evacuation" of residents from four settlements, he added, which would see more than 2,000 people moved.

Footage posted on the Telegram account of state-backed Izvestia newspaper purporting to show footage of the fire showed plumes of black smoke billowing into the sky.

Two Russian online media outlets reported that detonations had been audible in the area for over two hours.

Bus traffic on interregional routes had been "temporarily redirected," Nikolay Lukashenko from Crimea's Transport Ministry wrote on Telegram.

The Tavrida highway connects the eastern Crimean port of Kerch to Sevastopol on the peninsula's Black Sea coast in the west, according to Russia's TASS news agency.

Russia annexed Crimea from Ukraine in 2014, a move not recognized by the international community.

Kyiv has repeatedly said it plans to take back the peninsula.