Russian forces suffering massive frontline losses have deployed the world’s largest nuke-capable mortar weapon to the battlefield.

Dubbed “the Sledgehammer” the 2S4 Tulip – or Tyulpan – self-propelled mortar is 240mm wide – twice the size of NATO mortars which are 120mm.

Transported on its own tracks, it has a range of 12 miles and is used to obliterate large fortifications, military equipment, or troop positions.

It is capable of firing nuclear bombs, although it is likely this would be limited to “micro-nukes” aimed at destroying an area the size of a football stadium.

The heavy mortar weapon has already seen service in Afghanistan, Chechnya and Syria, with devastating effects.

It can also fire armour piercing, laser-guided, and outlawed cluster munitions, as well as tactical nuclear weapons.

Moscow’s commanders are desperately trying to hold back a ferocious counter-offensive by Ukraine’s forces all along the eastern front.

One security source told the Daily Mirror: “This is a huge weapon, devastating when using conventional weapons and capable of smashing a large area.

“But they will also be a very large target for Ukraine’s drone and artillery teams, who are hunting down Russia’s offensive equipment daily.

“The 2S5 is capable of targeting something from beyond its line of sight with bombs that would be very difficult, if at all, to deflect or intercept.”

The notorious Wagner Group of mercenaries – dubbed “Putin’s private army” – has suffered thousands of losses in the Bakhmut area of Donbas.

Most of Russia’s fighters in this area, scene of the worst fighting so far, are from Wagner Group, which has more than 50,000 soldiers in Ukraine.

It is feared President Vladimir Putin is poised to deploy a further 500,000 troops in a new mobilisation drive across the Russian Federation.

And Wagner Group commander Yevgeny Prigozhin has relaunched his recruiting drive in prisons across Russia, hiring murderers, sex attackers, and other criminals.

They are signed up in exchange for the promise of good pay and freedom from prison six months after they have fought in Ukraine.