BEIRUT (Reuters) - Three members of the Revolutionary Guards and three Islamic State militants were killed in clashes in the west of Iran on Saturday, a top Guards’ commander said, according to Tasnim news agency.

A team of 21 Islamic State fighters were tracked after they crossed Iran’s western border before being attacked by the Guards, the most powerful military force in the Islamic Republic, according to Sepah News, the Guards’ official news site.

General Mohammad Pakpour, head of the Guards’ ground forces, said 16 militants were arrested and two fled but were now surrounded, Tasnim agency reported.

In June, Islamic State militants attacked the parliament in Tehran and mausoleum of the Islamic Republic’s founder Ayatollah Ruhollah Khomeini, killing at least 18 and wounding dozens.

The attackers in the June assault were all Iranian Kurds from the Kurdish region of western Iran near the Iraqi border.

The Guards fired several missiles at Islamic State bases in Syria on June 18 in response to that attack.