Facebook has taken down an event that coordinates a raid of Area 51, the classified military base located in Nevada.

On Aug. 3, Saturday, Matty Roberts, the user behind the event, posted a screenshot of the notification he received on his personal profile. Facebook said the event "went against" community standards.

"I never got any reason behind the event being removed," Roberts told CNET.

Looking For Aliens At Area 51

In July, Roberts created a tounge-in-cheek event called "Storm Area 51, They Can't Stop All Of Us." The plan was to meet up at the military base, "Naruto Run" (a reference to a popular anime) to dodge incoming bullets, and "see them aliens."

Since then, over 2 million people have signed up to join the raid. It gave birth to several memes on Twitter and Reddit. It also captured the attention of popular celebrities, including late night talk show hosts Stephen Colbert and Jimmy Kimmel.

However, the event received a stern warning from the military. Speaking to The Washington Post, Laura McAndrews, a spokesperson for the U.S. Air Force, explained that Area 51 is a training range for the armed forces.

"The U.S. Air Force always stands ready to protect America and its assets," she stated.

Roberts did not actually want to coordinate a raid of Area 51. The event was started as a joke and he is now planning an Area 51 festival on Sept. 20, when the raid was supposed to take place, at a location that is not a military base in Rachel, Nevada.

He said that he created another Facebook event page for the festival but that, too, was taken down. He said he was expecting around 20,000 people to attend.

Facebook is yet to issue a comment regarding the event.

Are There Aliens In Area 51?

The event is based on the popular conspiracy theory that scientists working for the government are reverse-engineering alien technology at Area 51. A testimony from a retired Army colonel, who claimed that he was given access to extraterrestrial materials from a UFO that crashed in Roswell in 1947, further fueled the belief that the government is trying to hide evidence of aliens on Earth.

Others claim that the military base is where the government studies time travel.

However, in 2013, the CIA issued a declassified report revealing that U-2 spy planes were developed and tested in Area 51.