The United States says a member of Iran's Revolutionary Guard Corps is suspected of playing a role in an alleged plot revealed Tuesday to assassinate the Saudi ambassador to the U.S.

Iran Tuesday called the U.S. allegations a fabrication. But the U.S. says the Revolutionary Guard is involved in plotting terror worldwide.

The Revolutionary Guard was established by Supreme Leader Ayatollah Khomeini shortly after the 1979 Islamic Revolution. It is comprised of naval, air and ground forces.

U.S. officials say the Revolutionary Guard suspect identified as a conspirator in the plot is a member of the secretive Quds Force, the elite unit of the Revolutionary Guard. U.S. officials believe the Quds Force mostly operates outside of Iran.

Analysts estimate the Revolutionary Guard has at least 125,000 active members. The group controls the Basij Resistance Force, a paramilitary wing.

The Revolutionary Guard's influence extends into the political realm. President Mahmoud Ahmadinejad is among the prominent politicians who served in the group.