TEHRAN: Iranian security forces on Tuesday killed three Sunni militants in a firefight in the country's west, the police said.

According to the report, posted on the official police website, the firefight took place in a neighborhood in the city of Kermanshah, about 500 kilometers (310 miles) southwest of the capital, Tehran.

The police confiscated a Kalashnikov assault rifle and a suicide vest at the site of the clash, the report said. It did not identify the militants, though it called them "takfiris," a derogatory term in both Arabic and Farsi referring to extremist Sunni Muslims — such as members of the Islamic State group — who accuse other Muslims of being infidels.

Later in the day, Kermanshah Gov Asadollah Razani told the official IRNA news agency that security forces on Monday killed another member of militants he described as "takfiri Daesh." Dauesh is an Arabic language acronym for the Islamic States group.

Several members of the group were also arrested, Razani said, adding that grenades, pistols and automatic weapons were confiscated from them. IRNA said the group was planning to "kill and massacre innocent people."

Earlier this month Iran executed 20 convicted members of Sunni militant groups. And in June, Tehran announced it had broken up one of the "biggest terrorist plots" ever on its soil by Sunni extremists.