Rapper Kid Ink was arrested early Saturday in Las Vegas for disturbing the peace ... which raises the question, is there really peace in Vegas?
Law enforcement sources tell TMZ ... cops raced to 1Oak nightclub in the Mirage just before 3 AM after a 911 call about a fight in the club.
Several eyewitnesses tell us ... Kid Ink's female friend started the scuffle.
We're told the woman was acting belligerent as the 2 left the club ... and when security confronted them the "Show Me" rapper and his crew started getting physical.
Police hauled the rapper and his female friend off to jail. The woman was booked for giving a false statement to officers -- we don't know what she told them -- and Ink was booked for disturbing the peace.
He'll be released Saturday afternoon without posting bail. He's ordered to appear in court Monday.
UPDATE: A rep for Kid Ink claims the rapper and some of friends were taking photos on the closed red carpet ... but when there was an issue between a third party and security -- police stepped in.