Young Thug Had a Scary Run-In with SWAT

Young Thug and his crew came face-to-face with loaded guns during a scary misunderstanding with Pittsburgh cops ... TMZ has learned.

It all went down Sunday night after Young Thug performed at Summer Jam at Southside Event Center. Law enforcement sources tell us security at the venue alerted cops after they said they saw someone in YT's entourage brandishing a gun.

TMZ got this video showing cops and SWAT rushing toward Young Thug's sprinter van.

A source close to Young Thug tells us his team did have 4 guns on them, but they were all licensed to carry ... and presented the paperwork to officers.