Ella Langley Concert

4:12 PM PT -- Tulsa Police Department posted a statement on Facebook, saying they found "no credible threat" after "a call was made threatening the lives of people attending the event."

Police say the caller threatened to do "great harm" to concertgoers, through "shots fired and bombs."

They said they did a sweep with their bomb dogs after the call and didn't find anything.

Police insist they would never tell anyone to cancel their event if they couldn't find a credible threat. They say neither the police nor the BOK Center pulled the plug ... explaining it was Ella's team who decided to back out.

Ella Langley won't be taking the stage in Oklahoma tonight ... her show's been canceled due to a "serious security threat."

Tulsa's BOK Center took to social media to announce the abrupt cancellation, writing ... "Due to a serious security threat involving the safety of fans, venue personnel, and the artist, Ella Langley's scheduled performance tonight at BOK Center in Tulsa has been canceled."

The venue went on to say that safety was their top priority, and that's why they decided to pull the plug on the performance.