Gruesome new images have emerged showing Islamic State militants stoning a blindfolded and bound man and woman to death in Iraq after they were accused of having sex before marriage.

Taken in the ISIS-stronghold of Mosul in Nineveh province, the shocking images show a large crowd gathered to watch the jihadis murder the defenceless couple.

Young boys clamber onto their fathers' shoulders to get a better view of the man and woman being charged with 'fornication', before the familiar white-bearded face of ISIS's elderly Mosul-based executioner-in-chief Abu Ansar al-Ansari orders their stoning to death.

Stoned to death: Taken in the ISIS-stronghold of Mosul in Nineveh province, the shocking images show a large crowd gathered to watch the ISIS militants murder the defenceless couple

Accusation: An Islamic State militant with a yellow scarf covering his face is seen using a microphone and PA system to read out the charge of 'fornication' -or sex outside marriage - against the couple

The sickening images begin by showing a large crowd gathered in a rain-drenched square in central Mosul.

With heavily armed militants taking up positions on ledges overlooking the crowd, the young men and boys jostle to ensure they get the best view of the murder

In the background of the image, women wearing black niqabs are seen gathered together.

An Islamic State militant with a yellow scarf covering his face is then seen using a microphone and PA system to read out the charge of 'fornication' against the couple, suggesting they have been accused of having sex without being married, not of committing adultery.

A large pile of stones are then seen heaped in the middle of the road, before the barbaric ISIS militants began throwing them at the defenceless and blindfolded couple, who have had their hands bound to prevent them getting away.

As stones rain down on the victims' bodies, large pools of blood appear in the road, before eventually the man and woman die of their injuries and the savagery finally comes to an end.

Bloodthirsty: With heavily armed militants taking up positions on ledges overlooking the crowd, the young men and boys jostle to ensure they get the best view of the murder

Preparing to kill: After the charges are read out, the familiar white-bearded face of ISIS' elderly Mosul-based executioner-in-chief Abu Ansar al-Ansari (centre) orders their stoning to death

The images emerged as Iran's Revolutionary Guard this morning said a U.S. drone strike killed two of its advisers in Iraq, though the U.S. said it has only struck militants in its campaign against ISIS.

The claim came as negotiators attempted to reach a deal on Iran's contested nuclear program, which hard-liners in the Islamic Republic have opposed as giving away too much to the West.

The Guard said on its sepahnews.ir website the strike happened March 23, just after the U.S.-led coalition began airstrikes to support Iraqi forces trying to retake the Islamic State-held city of Tikrit.

It identified the dead as Ali Yazdani and Hadi Jafari, saying they were buried yesterday. It called them advisers, without elaborating on whether Iran contacted Iraqi or U.S. forces after the strike.

Iran occasionally reports on the death of its forces in Iraq and Syria, where it is backing embattled President Bashar Assad, but this is the first time Iran has said it has lost forces in an attack by the U.S. in those campaigns.

Barbaric: The Islamic State militants begin throwing stones at the defenceless and blindfolded couple, who have had their hands bound to prevent them getting away

Horrific: Young boys clamber onto their father's shoulders to get a better view of the sickening murder

NOW ISIS TURN THEIR SAVAGERY ON THE DEAD BY SMASHING GRAVES AND TOMBS IN SYRIAN CEMETERY Militants fighting for the Islamic State have now turned their savagery on the dead, tearing down graves and smashing tombs at a cemetery in Syria. Not content with the rape and massacre of the estimated four million brutally oppressed people living under the terror group's control in Syria and Iraq, ISIS jihadis are now victimising the dead. Claiming gravestones and tombs are a form of veneration of the dead and only distract from the worship of Allah, the heavily-armed, camouflage-wearing militants are seen happily reducing the hilltop cemetery to piles of rubble. The chilling images are believed to have been taken in the Syrian province of Raqqa and shows a hilltop cemetery overlooking what appears to be farmland. Having parked their motorcycles at the gates of the graveyard, the militants are seen inside pulling over tombstones while sympathisers stand alongside them taking photographs. Advertisement

The U.S.-led coalition began a campaign of airstrikes and reconnaissance missions around Tikrit, Saddam Hussein's hometown, on March 21 in support of large-scale operations to retake it after Iraqi efforts had stalled.

The U.S. Embassy in Baghdad said: 'The international coalition is aimed at Daesh only,' using an alternate Arabic acronym for the Islamic State group.

'All airstrikes are carried out at the request of the Iraqi government and in full coordination with the (Iraqi) Ministry of Defense,' the embassy said, without directly addressing the Iranian claim.

ISIS now controls a third of both Iraq and neighboring Syria. The U.S. began airstrikes against the group in August, while Iran has offered advisers and other assistance to Iraq to fight the extremists.

The offensive to retake Tikrit largely has been waged by Iraqi troops and Shiite militias advised by General Qassem Soleimani, commander of the Guard's elite Quds Force.

Several Shiite militias announced last Thursday that they would boycott the Tikrit operations due to U.S. involvement.

But General Lloyd Austin, the head of U.S. Central Command, told a Senate hearing Thursday that the U.S. agreed to Iraqi government requests to support the operation on the condition that the militias wouldn't be involved.

Mouin al-Kadhimy, a spokesman for the Popular Mobilization Units, the government-backed body overseeing the various militias, said it was not aware of reports that Iranians were killed near Tikrit.