Hero Ukrainian defenders in Mariupol using network of tunnels under steelworks to stage last stand against Russians

HERO Ukrainians defending Mariupol are using tunnels underneath a steelworks to stage a last stand against the Russians. Vladimir Putin’s forces have been besieging the southern port since the early days of the war, with large parts of it reduced to rubble by constant air and artillery pounding. Troops from the Ukrainian 36th Marine Brigade and the Azov Battalion are currently holed up in the Azovstal iron and steel works. The plant has a series of bunkers underneath it, dating from the Cold War when they were built to protect its workers from nuclear attack. The highly secure, maze-like bunkers are thought to contain around 1,500 Ukrainian troops and go six storeys underground. Alexander Grinberg, analyst at the Jerusalem Institute for Strategy and Security, said the Russians face treacherous task clearing the bunkers. READ MORE ON UKRAINE SICK SWAP Wife of Putin pal seized in Ukraine begs for swap with captured Brit fighter 'SO DISAPPOINTED' Zinchenko slams former team-mates for not condemning Ukraine invasion “They can try, but they’ll be slaughtered because the defenders of the tunnel will absolutely have the tactical upper hand,” he said. “Perhaps the only reliable way to clear the place out would be to use a chemical weapon, or chlorine gas, but that would be quite complicated to funnel into the system and obviously would risk escalating the wider conflict. “It’s up to the Ukrainians whether they choose to surrender or instead fight until the very last man. “So far, from what we have seen, they do seem to be choosing to fight to the last man.” Most read in News TORMENT My baby son was killed by his mum or her lover but no one has ever been convicted EVIL BARGAIN Russian soldier's wife 'tells him to rape Ukrainian women' in sick phonecall 'LIKE A PRISON' Rats and mice BITE my two young kids in their sleep in our hellhole flat HERO 'TORTURE' Captured Brit hero will NOT be treated as Prisoner of War, Russia warns BUG ALERT Urgent Kinder eggs warning at Easter as 70 kids in UK fall sick with salmonella ORCA HELL World’s worst killer whale attacks as beasts savage and try to drown trainers Among those who have been defending Mariupol was Brits Aiden Aslin and Shaun Pinner, who were paraded on TV after being captured. Brave Aidan surrendered after his unit ran out of food and ammunition in the city and was paraded on Russian TV on Thursday with a gash across his forehead and an eye half-closed. Michael Clarke, Visiting Professor of Defence Studies at King’s College London, said the defenders  can use the tunnels “to get around and pop up and carry out raids”. “They are going to go down fighting and the longer they can hold out the more they will stop Russians being able to redeploy north, which is what Putin really wants them to be doing,” he added. Fighters have in the past used tunnel systems to great effect in their struggle against superior forces. The Viet Cong made the vast Cu Chi tunnel system near Saigon a base for attacks against US troops and Hamas has used tunnels in their fight against the Israeli army. The Islamic State group’s tunnel system in Mosul, Iraq, allowed its fighters to surprise American troops with sudden appearances seemingly out of nowhere. But the most memorable example dates back to World War II and the battle of Stalingrad with its fierce fighting in the Red October industrial complex. Read More on The Sun ON YOUR MARKS Harry & Meg show fun side in mini cars at Invictus Games after Palace talks BACK ON? Katie Price and ex Carl spotted holding hands at the airport after shock split A sapper unit discovered a former factory used by German troops, stacked three tonnes of explosives underneath and blew up the entire complex, burying the Germans in the rubble. The astute use of tunnels has lost none of its effectiveness in the 80 years since, rendering enemy artillery, air strikes and snipers virtually useless. ReutersRussian forces heading to the besieged city of Mariupol[/caption] EyevineExperts have said the Russians will have to fight hand-to-hand for the steel works[/caption] Kommersant Photo / PolarisThe city has been devastated by the fighting[/caption] Help those fleeing conflict with The Sun’s Ukraine Fund PICTURES of women and children fleeing the horror of Ukraine’s devastated towns and cities have moved Sun readers to tears. Many of you want to help the five million caught in the chaos — and now you can, by donating to The Sun’s Ukraine Fund. Give as little as £3 or as much as you can afford and every penny will be donated to the Red Cross on the ground helping women, children, the old, the infirm and the wounded. Donate here to help The Sun’s fund Or text to 70141 from UK mobiles £3 — text SUN£3£5 — text SUN£5£10 — text SUN£10 Texts cost your chosen donation amount (e.g. £5) +1 standard message (we receive 100%). 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