More than 2,000 residents are being evacuated from four villages in Russian-occupied Crimea after a fire that triggered hours of explosions at a nearby ammunition depot.

Russian-installed officials also shut a stretch of the motorway that crosses the southern half of the peninsula.

They did not explain the cause of the fire at a military training ground near the city of Staryi Krim.

But unconfirmed reports on social media spoke of three Ukrainian strikes.

The overnight explosions coincided with a heavy Russian missile and drone attack that officials said was largely targeted at Ukraine's southern city of Odesa.

Critical infrastructure and military facilities were attacked by several waves of cruise missiles and Iranian-made drones launched from the Black Sea, Crimea and southern Russia, said Ukraine's air force.

Although 37 Russian missiles and drones were shot down, a number did penetrate Ukrainian defences. Officials in Odesa said a number of people were wounded and several flats were damaged. A grain and fuel terminal at the port were hit along with two warehouses including one described as housing fireworks.

It was the second night in a row that Odesa was targeted, in attacks linked to Russia's withdrawal from an international deal enabling grain and fertiliser to be exported safely across the Black Sea.

Port fuel facilities were damaged in the earlier attacks on Odesa, which is a key hub for Ukraine's grain exports.

Russia had called its attack on Odesa a "mass revenge strike" for an attack on the Russian-built bridge over the Kerch strait linking Crimea to Russia. Seaborne drones have been blamed for Monday's bridge strike that knocked out a section of bridge and killed a Russian couple.

The fire at a munitions depot in Crimea on Wednesday closed a 12km (7.5-mile) section of the Tavrida highway that links the cities of Simferopol and Sevastopol to the bridge. Construction of the road by Russia's occupation authorities began in 2017.

A series of explosions were heard in the area from around 04:30 (01:30 GMT) on Wednesday.

Russia's appointee-boss in Crimea, Sergei Aksyonov, said the cause of the fire at the military range was being investigated but that no-one was hurt.

He said four settlements housing some 2,200 people close to the range in Crimea's Kirovskyi district were being evacuated.