The Muslim Student Followers of the Imam's Line ( Dânešjuyân Mosalmân Piru Xatt Emâm), also called the Muslim Students of the Imam Khomeini Line, was an Iranian student group that occupied the U.S. embassy in Tehran on 4 November 1979. The students were supporters of the Islamic Revolution who occupied the embassy to show their support for Ayatollah Khomeini and their outrage that the ex-Shah of Iran was admitted to the United States for cancer treatment, instead of being returned to Iran for trial and execution. The occupation triggered the Iran hostage crisis where 52 American diplomats were held hostage for 444 days.