Dramatic footage appears to show Ukrainian air and sea drones targeting Russian Black Sea fleet

Incredible footage is believed to show how Ukraine targeted Russia's Black Sea fleet in a combined attack using air and sea drones – thought to be the first assault of its kind.

The images captured appear to show Ukrainian drone boats sneaking into the Crimean port of Sevastopol.

Russian ships and helicopters strafe the sea with bullets in an attempt to shoot the Unmanned Surface Vehicles (USVs) out of the water.

• Ukraine: Jaw-dropping cockpit footage of helicopter flying extremely low along highway
• Footage showcases Russian army recruits desperately short of the basics
• Russia releases footage of two Britons caught fighting with Ukraine

The level of damage inflicted on the Russian Black Sea fleet is still not entirely clear.

Watch: Ukrainian people 'will not fall' amid Russian drone attacks, Zelensky says.

What it has shown, however, is how effective relatively low-tech unmanned weapons can be, and how difficult they are to defend against.

The attack began under the cover of darkness, with infrared cameras searching for targets, before a USV rammed into the side of a ship.

The assault continued into daylight, with the cameras showing the drones speeding towards their targets.

The Russian Navy said it destroyed seven sea drones and nine airborne UAVs – the first time they have been used together in an attack.

Moscow claimed just one of its minesweepers suffered minor damage.

Kyiv has remained quiet about the raid.

Moscow has used the USV assault as a pretext to stop all grain shipments from Sevastopol, claiming it has evidence one of the drones was launched from a civilian cargo ship using the port. 

The office of Ukraine's President Volodymyr Zelensky accused Russia of mounting the attacks itself to deliberately scupper the grain deal. 

The Kremlin also accused the Royal Navy of helping plan the attack, which the Ministry of Defence (MOD) described as a falsehood of an "epic scale".