Updated

A man is accused of brandishing a gun at an Alabama immigration protest, where terrified demonstrators dropped to the ground in a park when people started shouting "Gun!," authorities said.

Shane Ryan Sealy, 34, was arrested at Saturday's rally in Huntsville, Huntsville police Lt. Michael Johnson said. He's charged with menacing and reckless endangerment.

Sealy is accused of picking a fight with a protester and then pulling out a gun after the protester pushed Sealy back and knocked him down, Johnson said.

"He pulled out a gun. I saw him holding it out in front of him. We just started screaming for everybody to drop to the ground," Ava Caldwell, an organizer of the "Families Belong Together" rally, told WHNT-TV . "We all dropped to the ground crying."

Initially, Sealy was "just heckling" and carrying a sign calling for people to be deported, said Heather Resendez, another organizer of the event.

"It wasn't an emergency at that point," Resendez told WAFF-TV. "But when he pulled out the gun, things escalated really quickly."

No shots were fired, authorities said.

Sealy taught at Huntsville's Grissom High School for a brief time in 2016 but hasn't worked for the school system in the past couple of years, Huntsville City Schools spokesperson Keith Ward said. He is a certified high school English teacher, Al.com reported , citing records from the Alabama Department of Education.

Cellphone video posted by WAFF-TV shows police responding to the incident.

Jail records do not list an attorney for Sealy.