The Arlington County Fire Marshal’s office is investigating a grass fire that ignited in front of an elementary school Monday afternoon.

The fire was reported around 1:30 p.m. and scorched a 20 by 40 foot area in front of Drew Model School (3500 23rd Street S.) in the Nauck neighborhood, according to fire department spokeswoman Lt. Sarah Marchegiani. Witnesses told authorities that the fire was sparked by individuals who were setting off fireworks, though no fireworks were found by investigators.

“The fire is still under investigation,” Marchegiani said. The blaze caused “minimal damage.”