Traffic on the key bridge connecting Crimea to Russia's mainland has been halted amid reports of explosions.

The health ministry in Russia's Krasnodar region, which lies at the eastern end of the bridge, said two people were killed in an unspecified accident on the bridge and their daughter was injured.

The governor of Crimea, which was annexed by Russia in 2014, announced the closure early Monday but did not specify the reason.

News reports said local residents heard explosions before dawn, but there was no confirmation.

The extent of the damage was not immediately clear, but Governor Sergei Aksyonov said he expected rail traffic on the bridge to resume within several hours.

The 19-kilometre bridge that was opened in 2018 is the main land connection between Russia and the Crimean peninsula.

The bridge that spans the Kerch Strait was damaged in October by a truck bomb and required months of repairs before resuming full service. The bridge carries both road and rail traffic and is an important supply artery for Russia's war in Ukraine.?