Ronnie Ortiz-Magro Baby Mama Jen Harley has been arrested

EXCLUSIVE

Ronnie Ortiz-Magroit's baby mom, Jen Harley, was arrested for a New Year's Eve incident while she allegedly threw an ashtray at the reality TV star … TMZ learned.

Harley was arrested in Vegas on Thursday morning around 3 am on a warrant issued last month. Police forces tell us … Jen called the cops early Thursday morning and said someone had a gun. The police responded, came home and when they did a background check, they discovered that she had an outstanding warrant.

TMZ broke the story … Ronnie filed a battery report against Harley on January 3, after the two men engaged in a decisive battle at a Vegas club on New Year's Eve. During their argument, Harley reportedly thrown an ashtray at Ronnie's, striking him in the face and cutting his nose, lips and forehead.

That night we got a video of the club showing Ronnie coming out and bleeding.

The fight did not stop there … when Jen came home that night, she would have found his house ransacked … accusing Ronnie of having broken a flat-screen TV, picture frames and a vase. He was also recorded breaking the security camera in front of his door back in December.