Updated: 2:08 p.m. | Posted: 9:54 a.m.

Following a Thursday night performance at Milwaukee's Summerfest, Lizzo issued a series of tweets that called out one of the festival's security guards for attacking members of her production team.

In the first tweet, Lizzo alleges the security guard "slapped and manhandled" her hair stylist and stylist, and she asks if anyone present has video of the incident.

Lizzo describes the incident as racially motivated. In a later tweet, Lizzo called her Milwaukee set the "best show ever," but declared "I feel like I can't even celebrate cuz RACISM don't matter if you a headliner."

Lizzo's stylist, Marko Monroe, gave his account of the incident via his Instagram account. A transcript of Monroe's full account appears below (note: transcript includes profanity). In recounting the events, Monroe says he was taking photos and video of Lizzo's performance when a security guard confronted him. "He then grabs my arm and puts it behind my back," Monroe says. "I'm like, 'I work here, look at my badge,' and he was not listening and he escorted me off the stage."

Meanwhile, Lizzo's hairstylist, Shelby Swain, commented on her own Instagram. "Y'all got some dumbass people in Milwaukee," Swain said. "Just dumb, racist, homophobic, all of that plus more. We all work with Lizzo … I have an all-access pass. The whole camp has."

Summerfest issued a statement saying it is investigating. Posting on Twitter, Summerfest wrote, "Lizzo gave an incredible performance which she now feels is tarnished by events which occurred during the performance. We do not tolerate racism in any form. We will conduct a thorough investigation.

"We have an experienced crowd management staff who strive to protect performers and fans. While there may be challenges during a performance, we expect those challenges to be handled professionally & respectfully. If those standards were not met, we will take appropriate action."

In response to the statement from Summerfest, Lizzo tweeted, "Tonight was beautiful. You are beautiful. But the struggle ain't over. Racism and bigotry don't care if you're a headliner. Thank you @summerfest. We will be filing a complaint against that bigoted 'security' guard and I hope you'll be cooperative in seeking justice."

Lizzo performs at Glastonbury on Saturday, June 29, followed by a series of European dates. In the meantime, she has asked for any additional photos or videos of the Milwaukee incident as an aid in the investigation.

This is a developing story: We'll give updates on the situation as we learn more.