UFO enthusiasts from around the world have descended on a remote Nevada town near the once-secret Area 51 military base.

Alien-hunters are arriving near Area 51 after a viral craze that saw them commit to storm the mysterious US military base as a variety of events are taking place to mark the weekend, including music festivals in a variety of locations.

The "Storm Area 51" invitation spawned festivals in the tiny Nevada towns of Rachel and Hiko nearest the military site, and a more than two-hour drive from Las Vegas.

About 75 people arrived early Friday at a gate at the once-secret Area 51 military base in Nevada — at the time appointed by an internet hoaxster to “storm” the facility to see space aliens — and at least two were detained by sheriff’s deputies.

Lincoln county sheriff said about 1,500 people headed to two desert towns in response to the internet hoax to ‘raid’ the base

Sound checks echoed from a distant main stage while Daniel Martinez whirled and danced at dusty makeshift festival grounds just after sunset in Rachel, the Nevada town closest to the once-secret Area 51 military base.

For sociologist and pop culture expert, event that was born without pretensions on Facebook risks becoming a security crisis in a protected area of the U.S. government.

Authorities admit they don't know what to expect as the 'Storm Area 51, They Can't Stop All of Us' event kicks off in rural Nevada.

About 75 people arrived early Friday at a gate at the once-secret Area 51 military base in Nevada - at the time appointed by an internet hoaxster to "storm" the facility to see space aliens - and at least two were detained by sheriff's deputies.