Iranian police say security forces have killed three armed Sunni militants in a firefight in the country's west.

The report, posted on the official police website, says the firefight took place on Tuesday morning in a neighborhood in the city of Kermanshah, which is located about 500 kilometers, or 310 miles, southwest of the capital, Tehran.

It says police confiscated a Kalashnikov assault rifle and a suicide vest at the site of the clash.

The report didn't 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.

Earlier this month Iran executed 20 convicted members of Sunni militant groups.