Colonel Sohrab Hosseinnejad, head of the police intelligence department in the southwestern province of Khuzeshtan, were the robbery happened, said the passenger bus had been stopped by what appeared to be a police car while it was travelling on the road between the cities of Ahvaz and Masjed-e Soleiman.
The armed muggers, disguised as police officers, then entered the bus, intimated the passengers and took away their belongings, he said.
Footage of the theft went viral on social media, prompting calls for a swift police response to the crime.
During a special two-stage operation, police forces identified and arrested two of the main culprits, the official added.
He said wireless phone, a Kalashnikov, a police flasher, a bulletproof vest and a fake license plate were discovered from their hideout.
Another member of the gang was also taken into custody in the second phase of the operation.
The arrestees have a history of theft and have so far confessed to four cases of armed robbery and 10 cases of violent robbery.