Ilhan Omar

Rep. Ilhan Omar is going nuclear over Vice PresidentJ.D. Vance's declaration she's under investigation for alleged immigration fraud, telling TMZ DC ... the probe is nothing more than a racist, creepy, and weird conspiracy theory.

Jacob got the Congresswoman from Minnesota leaving her office on Capitol Hill, and asked her about the Veep breathing new life into claims she married her own brother to get U.S. citizenship.

Omar says Republicans have been out to get her since President Trump's first administration, but she denies any wrongdoing.

What's more, she says it should be obvious the prez and the Dept. of Justice have nothing on her ... because she's still on her J-O-B in DC.

Ilhan says it's disgusting and disturbing that so many people still believe the conspiracy theory, but, at this point, she says it's par for the course. If she's actually worried about a DOJ probe, her smile and body language definitely don't show it ... watch the video.

While she's down to cooperate with an investigation -- Rep. Omar says she has nothing to hide -- she's certain there's just one simple reason she's still on Trump's hitlist.