BAGHDAD: In March, a senior commander with the Islamic State group was driving through northern Syria on orders to lead militants in the fighting there when a drone blasted his vehicle to oblivion.

The killing of Abu Hayjaa al-Tunsi, a Tunisian jihadi, sparked a panicked hunt within the group's ranks for spies who could have tipped off the US-led coalition about his closely guarded movements.

By the time it was over, the group would kill 38 of its own members on suspicion of acting as informants.

They were among dozens of IS members killed by their own leadership in recent months in a vicious purge after a string of airstrikes killed prominent figures.

Others have disappeared into prisons and still more have fled, fearing they could be next as the jihadi group turns on itself in the hunt for moles, according to Syrian opposition activists, Kurdish militia commanders, several Iraqi intelligence officials and an informant for the Iraqi government who worked within IS ranks.

The fear of informants has fueled paranoia among the militants' ranks. A mobile phone or internet connection can raise suspicions. As a warning to others, IS has displayed the bodies of some suspected spies in public or used particularly gruesome methods, including reportedly dropping some into a vat of acid.

IS "commanders don't dare come from Iraq to Syria because they are being liquidated" by airstrikes, said Bebars al-Talawy, an opposition activist in Syria who monitors the jihadi group.

Suspects were rounded up, taken to military bases around Raqqa, and the purge ensued. Within days, 21 IS fighters were killed, including a senior commander from North Africa, Abdurrahman said.

Dozens more were taken back to Iraq for further questioning. Of those, 17 were killed and 32 were expelled from the group but allowed to live, Abdurrahman and al-Talawy said, both citing their contacts in the militant group.

Among those brought to Iraq was the group's top security official for its Badiya "province," covering a part of central and eastern Syria. His fate remains unknown.

Non-IS members are also often caught up in the hunt for spies. In the Tabqa, near Raqqa, IS fighters brought a civilian, Abdul-Hadi Issa, into the main square before dozens of onlookers and announced he was accused of spying. A masked militant then stabbed him in the heart and, with the knife still stuck in the man's chest, the fighter shot him in the head with a pistol.

Issa's body was hanged in the square with a large piece of paper on his chest proclaiming the crime and the punishment. IS circulated photos of the killing on social media.

According to al-Talawy, several other IS members were killed in the town of Sukhna near the central Syrian city of Palmyra on charges of giving information to the coalition about IS bases in the area as well as trying to locate places where al-Baghdadi might be.

Sherfan Darwish, of the US-backed Syria Democratic Forces, which has been spearheading the fight against IS in Syria, said there is panic in IS-held areas where the extremists have killed people simply for having telecommunications devices in their homes.

"There is chaos. Some members and commanders are trying to flee," Darwish said.

The US -led coalition has sought to use its successes in targeting IS leaders to intimidate others.

In late May, warplanes dropped leaflets over IS-held parts of Syria with the pictures of two senior militants killed previously in airstrikes. "What do these Daesh commanders have in common?" the leaflet read. "They were killed at the hands of the coalition."

The jihadis have responded with their own propaganda.

"America, do you think that victory comes by killing a commander or more?" IS spokesman Abu Mohammed al-Adnani said in a May 21 audio message. "We will not be deterred by your campaigns and you will not be victorious."