The M.E.K, short for the Mujahedeen-e Khalq or People’s Mujahideen of Iran, is an exiled Iranian opposition group that was previously designated a “foreign terrorist organization” by the State Department until its removal in Sept. 2012.
The M.E.K has a number of high profile backers in the U.S. Here's former House Speaker Newt Gingrich bowing to M.E.K. leader Maryam Rajavi in 2012. At the time the M.E.K was still labeled a terrorist organization by the U.S.
The The National Association of Iranian Academics in Britain took out a Washington Post ad in 2011, writing an open letter to President Obama asking him to take the M.E.K. off the list of terrorist organizations.