Iranian security forces have broken up a group linked to Islamic State which was planning attacks in religious centers in the country and trying to hide weapons in home appliances, state news agency IRNA reported on Monday,
The agency said the operation was conducted jointly with another country's agents and a total of 27 suspects were arrested. The agency did not name the other country.
Islamic State claimed responsibility for an attack in June in which suicide bombers and gunmen attacked the Iranian parliament and Ayatollah Khomeini's mausoleum in Tehran, killing 18 people.
It threatened more attacks against Iran's majority Shi'ite population, seen by the hardline Sunni militants as heretics.
Intelligence Ministry agents "were able to arrest a terrorist group linked to Daesh (Islamic State) that intended to carry out terror operations in religious cities ...," IRNA said.
"The terrorists were trying to bring (weapons and ammunition) into the country by concealing them in home appliances," the agency quoted a ministry statement as saying.
It said 10 people were arrested at the group's leadership center abroad and 17 people inside Iran. Five of the 17 were due to carry out the attacks in Iran and the other 12 were supporting them, statement said.
The statement did not identify the religious centers it said were the targets.
On Sunday, Iranian media said Iran's Revolutionary Guards had killed two people in clashes with a group of militants in the northwest of the country, where shootouts with Iranian Kurdish militant groups based in Iraq are common.
In June, Iran announced the arrests of the members of a group linked to Islamic State which had planned bombings and suicide attacks.