A man who allegedly threatened to launch a mass shooting if Joe Biden becomes president was taken into custody Friday in Los Angeles, a report said.

The local unidentified man was tracked down hours after unleashing his threat in video posted on Instagram, law-enforcement sources told the Los Angeles Times.

“At this point, like, if Biden gets in, I’m just gonna do like a school shooter, just take out all these Democrats and a few pedophiles on the way out,’’ the man said, according to video posted by TMZ.

“If I go to hell, I’m taking these motherf–kers with me,’’ he added.

The FBI and local authorities tracked the man down and cuffed him and took him into custody as officials search his home for possible weapons, the Times said.

The suspect was placed on a psychiatric hold, TMZ said — noting that authorities were particularly concerned with the threat because of a planned demonstration in downtown Los Angeles on Friday that they feared he might be targeting.