Mourinho’s side have been using UCLA’s Drake stadium as their base – a venue taken over by students, visitors and faculty members on Wednesday evening after a bomb threat.
A statement from UCLA read: “UCLA received a bomb threat on Wednesday evening and, as a precaution, ordered residents evacuated from campus housing at about 10.10pm.
“Many of the residents who were affected gathered safely in Drake stadium while emergency responders checked campus facilities. No suspicious device was found.
United are due to return to training at UCLA for a double session on Thursday, while Real Madrid will also be training just metres away at North Athletic Field.
A security team follows Mourinho’s side around the city, just as they do elsewhere on their travels, and UCLA security presence is visible around Drake Stadium.
United play five matches on their pre-season tour of the United States, kicking off against LA Galaxy on Saturday.