On Thursday, the Iranian Intelligence Ministry released the names of the five terrorists who were killed after carrying out the deadly attacks in Tehran.
The Wednesday terrorist attacks on Iran's Parliament and the Mausoleum of Imam Khomeini left 17 people dead and 50 others injured.
After offering condolences to the families of the attacks victims, Alavi stressed that over the past few months the country's intelligence forces had neutralized over 25 terrorist cells.
Iran says it has killed the alleged mastermind of twin attacks that killed 17 people in Tehran, and arrested almost 50 people in connection with those assaults, officials said. Members of Iranian forces are seen during a terrorist attack on the Parliament in central Tehran, Iran, on June 7, 2017.
"We possess documents and information showing the direct supports by the United States imperialism for this highly disgusting stream in the region which has destroyed the Islamic countries and created a wave of massacres and clashes", Deputy Chief of Staff of the Iranian Armed Forces Major General Mostafa Izadi said.
Seventeen people were killed when four armed assailants attacked the national parliament building, while a suicide bomber blew himself up a museum in the city.
Press TV quoted Iran's Intelligence Minister Mahmoud Alavi, as saying, in a televised interview on Saturday that the mastermind of terrorist attack on Iran's Parliament and the shrine of Ayatollah Khomeini on June 7 were killed earlier in the day by the intelligence forces.
It added that the terrorists were detained in the Iranian provinces of Kermanshah, Kordestan, West Azarbaijan and Tehran.
On Saturday, the authorities also announced the arrests of eight people in Alborz province, north of Tehran, who allegedly provided logistical support to the attackers.
"Tehran police announced on Saturday a vehicle used by terrorists to reach the attack sites was found in downtown Tehran".
Tehran police said the auto the attackers used on Wednesday was discovered on Saturday in the city centre.