They have already made a number of sickening threats as they lose ground in Syria and Iraq but have ramped up the violence in their latest campaign.

Sickening mocked-up images appear to show Ronaldo and Messi pinned to the ground, their heads held by masked jihadis in a packed football stadium, along with the caption “Your blood will fill the ground”.

The latest threat was revealed by cyber intelligence firm Sixgill, which monitors ISIS chatter, according to the Mirror.

It was released yesterday on Telegram by a pro-ISIS group.

The terrorist group earlier this month called on its supporters to launch attacks at the football tournament, which kicks off in Russia next month.

They made their call to arms on a sickening online propaganda poster showing a knife slashing the World Cup logo with a French caption translated as “kill them all”.

Previously, ISIS warned Vladimir Putin he will “pay the price for killing Muslims” in a poster showing a jihadist holding an AK-47 inside a packed football arena.

The threat was thought to be linked to Russia’s military support for Syrian President Bashar Al-Assad in his fight against ISIS.

In March, ISIS targeted Messi for the first time in posters showing him kneeling next to a jihadist and banged up behind bars.

Russian security services are on high alert for an ISIS-inspired attack on the tournament.

Last month Moscow revealed it had killed 11 Jihadists as they try to stamp out extremism ahead of the month-long showpiece.

The FSB security service has indicated terrorism is the main threat to the World Cup.

“Guns, bullets, knives and grenades were discovered at the scene,” said a statement from the Russian Investigative Committee, which probes serious crime.