Highline College near Seattle, Washington, ordered its campus on lockdown on Friday morning as police responded to unconfirmed reports of gunfire, according to the college and local police.
"This is not a drill," the college said in a message on its Facebook page, urging people to barricade doors and windows.
The Renton Police Department said it and other law enforcement agencies were sending officers after reports of "shots fired," it said on its Twitter account.
The college said police were evacuating buildings. The reports of gunfire were unconfirmed, and there was no confirmation of any injuries, police said.
The college is in Des Moines, a small city about 25 miles (40 km) south of Seattle, and has about 17,000 students, according to its website.