It was a strange and somewhat scary situation for Journey on Friday night ... 'cause the iconic band had to abruptly end a show due to an electrical fire on stage!

The '70s rockers were in the middle of their iconic tune “Don’t Stop Believin’” at the Houston Livestock Show and Rodeo in NRG Stadium -- when the stage suddenly went dark, audience footage shows.

The crowd kept belting the tune ... but they eventually stopped as they realized something was not right -- and we hear stagehands at one point rushed the stage with fire extinguishers.

Not long after all the commotion ... the audience was informed the night was over, an announcement reading in part ... "Due to an unforeseen electrical incident under the stage area, we regretfully announce the cancellation of tonight's Journey concert. We sincerely apologize to all fans for this disappointment."

Sounds like rescheduling options and/or refunds are in the works ... and thankfully, there were no reports of any injuries.

Once a makeup show is all squared away ... they gotta open with "Lights," right???