Iranian security forces killed five Islamic State (IS) militants in Iran on Saturday, official said.The clash followed the incursion of a 21-member team of the IS into the country through the western borders. In the day-long clash, 16 other IS militants were arrested, Xinhua reported.According to Islamic Revolution Guards Corps (IRGC), following the intelligence activities by its forces, the terrorist cell affiliated to IS were identified and the clashes erupted on Saturday morning in the west of Iran.Last year, six assailants attacked Iran's parliament and Imam Khomeini mausoleum in capital Tehran, whereby at least 17 people died and 52 others injured.All the six assailants involved in the attacks were killed. The IS has claimed responsibility for the attacks.