First-person footage shows Ukrainian fighters engaging in a shootout with Russian invaders in the Azovstal plant.

The video was filmed at the Azovstal iron and steel plant in the under-siege Ukrainian city of Mariupol on May 12.

Russian troops stormed the city on April 19 and destroyed large areas. However, pockets of organised resistance fighters remain at the plant, refusing to surrender to the invaders’ demands.

Fighters of the Azov Battalion, a unit of the National Guard of Ukraine, are currently holed up in the battered Mariupol plant.

The battalion said: ‘The Azov Regiment is doing the impossible. On the 78th day of the full-scale war, despite the extremely difficult situation, lack of ammunition and a large number of wounded, fighters of the Azov Regiment continue to knock out the enemy from previously occupied positions at Azovstal.’

Also on Thursday May 12, the Ukrainian military said ‘a traitor’ told the Russian forces about their network of tunnels in the plant, leading to the enemy storming their positions this week.

The Ukrainian Centre for Strategic Communications said: ‘Yesterday, the enemy did not shy away from an attempt to storm the grounds. Our main goal is to block the exits of the system of underground tunnels, which the enemy was shown by a traitor.

‘Despite this, our Defenders of Mariupol are trying to counterattack, risking everything said Petro Andryushchenko, adviser to the mayor.’

Russian troops invaded Ukraine on February 24 in what the Kremlin is still calling a ‘special military operation". Today marks the 79th day of the campaign.

From February 24 to May 12, the total combat losses of Russian troops stand at around 26,650 personnel, according to the General Staff of the Armed Forces of Ukraine.

The Ukrainian military also claims that Russia has lost 1,195 tanks, 2,873 armoured fighting vehicles, 534 artillery systems, 191 multiple launch rocket systems, 87 anti-aircraft systems, 199 warplanes, 161 helicopters, 2,019 motor vehicles and fuel tankers, 13 vessels, 398 unmanned aerial vehicles, 41 units of special equipment and 94 cruise missiles.

Meanwhile, Ukrainian President Volodymyr Zelenskyy has warned that the Russian blockade of Ukraine's Black Sea ports threatens global food supplies.