The ministry has yet to reveal whether the 27 arrested were involved in June's attacks. According to the Intelligence Ministry statement, 10 people were arrested at the group's leadership center overseas, and 17 people inside Iran.
"Intelligence agents succeeded in identifying and arresting a terrorist group linked to Daesh, who meant to conduct terrorist attacks in central provinces and religious cities", the statement said, referring to Isis using its Arabic name.
Police officers stand outside Iran's parliament building following an attack by several gunmen on June 7, 2017 in Tehran, Iran. The chairman Senate held bilateral meetings with Speaker Iranian Majlis Ali Larijani, who also hosted a banquet in his honour.
According to the Ministry, five terrorists were designated as would-be perpetrators of acts of terror in Iran while the others were in charge of procurement and providing support.
Iranian President Hassan Rouhani, who is being sworn-in for a further term on Saturday, has accused the United States of trying to undermine Tehran's nuclear deal with world powers, and urged European countries not to side with Washington.
IRNA reported that the operation was conducted jointly with another country's agents, but the country was not named. Weapons, ammunition, telecommunications equipment and detonators were reportedly seized. Eight people were killed in the attack and scores were injured.
It noted that 10 terrorists were arrested outside the country while 17 others were nabbed in the country. The report quoted a military prosecutor as saying the identity of the attacker and the suspected course of events would be made public after comprehensive reviews of the scene and interviews with witnesses and survivors.