(Tasnim) -- In a statement on Thursday, the ministry identified the five gunmen as Qayyoum, Abu Jihad, Ramin, Serias, and Fereydoun, without announcing their surnames.

According to the statement, the five attackers were terrorists with criminal backgrounds who were linked to “Wahhabi and Takfiri groups.”

After joining the ISIS terrorist group, the five men had left Iran and were engaged in the terrorist group’s operations in Iraq’s Mosul and Syria’s Raqqa, it added.

The five gunmen had returned to Iran in August 2016 for a terrorist operation under the command of Abu Aysheh, a ranking commander of ISIS, with the purpose of carrying out attacks in Iran’s religious cities, the statement said.

They had fled Iran after their cell was disbanded at the time and their ringleader, Abu Aysheh, was killed, it added.

On Wednesday morning, the five terrorists launched simultaneous attacks on Iran’s parliament building in downtown Tehran and on the mausoleum of late founder of the Islamic Republic Imam Khomeini, south of the city.

Dressed as women, the assailants attacked the parliament buildings in the morning. Equipped with AK-47 assault rifles, handguns and suicide vests, the gunmen killed security guards and ordinary people before holding people hostage in the upper floors of the building.

They were all killed by the security forces after an operation that took several hours.

In the other attack at the shrine of Imam Khomeini, one suicide bomber blew himself up while the second one was killed in a an exchange of gunfire.

The death toll from Wednesday's incidents in Tehran grew to 17, while more than 40 others have been wounded.