That group, the People’s Mujahedin of Iran, or MEK for short, was designated a terrorist organization by the U.S. State Department until 2012, at which point it was removed from the State Department’s terror list after an intense lobbying effort. The group was on the terror list for good reason: MEK has killed several American servicemembers and contractors; attempted to assassinate a top U.S. general; and attempted to kidnap the U.S. Ambassador to Iran, Douglas MacArthur II.

In 1992, the MEK conducted a terror attack on the Iranian mission to the United Nations in New York, making it one of the few terror groups to have operated on U.S. soil, according to Daniel Benjamin, the former coordinator for counterterrorism at the State Department.

The group has been widely characterized as a cult.