Iran has arrested 32 people who had expressed support online for a man accused of murdering a cleric, semi-official news agency ISNA reported on Tuesday.

Behrouz Hajilouyi allegedly shot Mostafa Ghasemi on Saturday outside the seminary where the Shia cleric worked in the western Hamedan province.

He had confessed to the crime in a now-deleted post on his Instagram account, Fars news agency reported.

“Thirty-two people who had left messages of support for Behrouz Hajilouyi on his personal (Instagram) page were identified and arrested,” Hamedan police chief Bakhshali Kamrani told ISNA.

Hajilouyi's Instagram account shows photos of him posing with pistols, shotguns and automatic rifles.

He was shot dead in a firefight with police on Sunday after his car was tracked, according to Kamrani who has not put forward a motive for the cleric's killing.

The murder prompted Iran's supreme leader, Ayatollah Ali Khamenei, to call on police to crack down on the online trade in firearms.

Murders of clerics have been rare in the Islamic republic in recent years. But in November, a Sunni imam was shot dead in the northeastern province of Golestan, according to state media.