BROOMFIELD, Colo. (AP) — Police responded Thursday to what they say is an active shooting at an apartment building in the Denver suburb of Broomfield.

Police released little information other than that officers have responded to shooting at the Arista Flats apartments and that the area wasn’t safe.

The city’s SWAT team, crisis negotiators and law enforcement from nearby communties are assisting, police said. A school near the scene has been locked down.

Some people were evacuated and police sent out a reverse emergency notification to area residents to shelter in place.

Broomfield is a city of about 75,000 people roughly 15 miles (24 kilometers) northwest of Denver.