A space observatory has been evacuated and placed on lockdown by the FBI, sparking claims of alien life from conspiracy theorists.

Alien life

Alien life

No explanation has been given for the events at the National Solar Observatory in Sunspot, New Mexico, which has been described as a ''precauntionary measure'' by the Association for Universities for Research in Astronomy.

Otero County Sheriff Benny House told the Daily News that his officers were placed on ''standby'' by the FBI.

He added: ''For the FBI to get involved that quick and be so secretive about it, there was a lot of stuff going on up there.

''There was a Blackhawk helicopter, a bunch of people around antennas and work crews on towers, but nobody would tell us anything.''