FNA- Iranian Deputy Police Chief Brigadier General Eskandar Momeni stressed that the country's intelligence and security forces inflicted heavy damage on the terrorists and their comrades after the recent attacks in Tehran which killed 17 people.

"The intelligence and security forces fully monitor the terrorists' activities; a number of key terrorists and their logistical forces have been captured and their operational and logistical forces have received very heavy blows," General Momeni told reporters in the Northern city of Sari on Sunday evening.

He assured the Iranian nation that the country's security forces will take a very hard revenge from the terrorists for their Wednesday attacks in Tehran.

Three male assailants fired several rounds at the guards protecting the parliament building in Tehran on Wednesday morning. The assailants opened their way into the parliament's administrative building while shooting at the guards.

A similar attack took place at the holy shrine of the late founder of the Islamic Republic, Imam Khomeini, parallel with the parliament attack.

17 people, including the parliament's guards, were killed and 52 others were wounded in the twin attacks.

The ISIL claimed the responsibility for both attacks.

Deputy Chief of Staff of the Iranian Armed Forces Major General Mostafa Izadi announced on Sunday that the country is in possession of evidence and documents proving Washington's direct support for the ISIL terrorist group.

"We are facing a proxy warfare in the region as a new trick by the arrogant powers against the Islamic Republic," Izadi said.

"As the Supreme Leader of the Islamic Revolution (Ayatollah Seyed Ali Khamenei) said, we possess documents and information showing the direct supports by the US imperialism for this highly disgusting stream (the ISIL) in the region which has destroyed the Islamic countries and created a wave of massacres and clashes," he added.