Call Security! Kailyn Lowry & Briana DeJesus Fight During 'Teen Mom 2' Reunion

A physical fight broke out on Saturday during the Teen Mom 2 reunion taping in New York City, RadarOnline.com can confirm.

The Ashley's Reality Roundup first reported that the set descended into chaos after enemies Kailyn Lowry and Briana DeJesus got into a brawl!

While filming the Unseen Moments special, DeJesus came out "ready to fight," a source told RadarOnline.com, adding that the two immediately "started arguing."

In a shocking move, DeJesus' sister, Brittany, grabbed Lowry's hair and pulled her to the ground, the source claimed.

As the insanity continued, "all the cast, including host Dr. Drew, ran off stage."

Pregnant Chelsea Houska was "very upset" that she would get caught-up in the chaos, the source continued.

Fortunately, security intervened to break up the fight.

According to The Ashley, cast member Jo Rivera fled the set after the brawl and headed home because he was so disgusted with the drama. 

The entire Teen Mom 2 family was present except Jenelle Evans. As RadarOnline.com reported, the controversial star boycotted the reunion because MTV refused to pay for her fired husband David Eason to attend as well.

Outspoken Evans took to Twitter after hearing about the fight.

"So glad I stayed home from NYC this weekend with my babies," she wrote. "Too much drama! #CalledIt."

As RadarOnline.com readers know, Lowry and DeJesus' bad blood began when the Teen Mom 2 newbie began dating the mother of three's ex-husband, Javi Marroquin.