A series of explosions have rocked Crimea, after a reported Ukrainian drone attack on the peninsula which was illegally annexed by Russia in 2014.

Video posted online shows a blast allegedly near a fuel depot in the south-eastern city of Feodosiya.

Russian officials said 38 drones had been shot down. The Kerch bridge which connects Crimea with Russia was temporarily closed.

The attack comes as Ukraine continues to urge allies to boost arms supplies.

Russian troops have recently made gains in Ukraine as Kyiv struggles to sustain its forces with Western-made arms. Moscow took control last month of the key eastern town of Avdiivka.

However, according to British military intelligence, this has come at a huge cost. In its latest update, it said February had been the deadliest for the Russians since the start of the full-scale invasion on 24 February 2022 - with 983 killed and wounded per day.

"Today, Russia has highly likely lost over 355,000 personnel killed or wounded during the Ukraine war," it said. It is not clear how the figure was reached.

Russia does not provide a record of casualties.

A few days ago, Ukrainian President Volodymyr Zelensky, said Ukraine had lost 31,000 troops since 24 February 2022. He also claimed that 180,000 Russian troops had been killed since then.

Russia has not reported any damage from the latest attack on Crimea, although eyewitnesses have reported windows shaking and car alarms going off. Kyiv has not confirmed its forces were involved.

On Saturday, a Russian drone hit a block of flats in the Ukrainian city of Odesa, killing at least 12 people, including five children. Sunday is a day of mourning in Odesa and the region.

In a separate development on Sunday, Russia targeted the southern Kherson region, killing one person and injuring another three, according to Ukrainian officials.

They also said 16 people were injured in Russian shelling of the town of Kurakhove, in Ukraine's eastern Donetsk region.

Russian forces have launched thousands of Iranian-made drones at Ukrainian targets since they invaded the country more than two years ago.

In retaliation Ukraine has targeted Russian sites, notably oil facilities.

On Saturday a drone struck a residential building in St Petersburg, Russia's second-largest city. About 100 people were evacuated and there were no reports of casualties.

With its airbases, troop concentrations, training grounds and the Black Sea fleet, Crimea has been a key target for the Ukrainians.

At one point last year, it was thought that it intended to launch a full-scale attack to retake the peninsula.

In particular, Ukraine has repeatedly hit Russia's Black Sea fleet. Satellite images last year showed many of the Crimea-based warships had left the peninsula for the Russian Black Sea port of Novorossiysk.

Last month, the Russian landing ship Caesar Kunikov was sunk off the coast of Crimea, according to Ukraine's armed forces.

Its sister ship Novocherkassk was hit while in port in Feodosiya in December last year.

In one of the biggest strikes on the Black Sea fleet, last September Ukraine attacked naval targets and port infrastructure, using as many as 10 missiles and three unmanned boats. It caused a large fire at a Sevastopol shipyard.

Ukraine's biggest scalp in naval warfare has so far been the sinking of Russia's flagship Black Sea missile cruiser, the Moskva, in April 2022.

Ukraine has also targeted the Kerch bridge several times as it is an important resupply route for Russian forces occupying parts of the country's south.

Kyiv has repeatedly said it plans to retake Crimea and all territories seized by Russia.

Ukraine is critically dependent on weapons supplies from the US and other Western allies to keep fighting Russia - a much bigger military force with an abundance of arms and artillery.

Ukrainian troops have been running out of ammunition as supporters of former US President Donald Trump in Congress refuse to approve a $61bn (£48bn) military aid package.