Students at high schools across the U.S. are staging walkouts to protest gun violence in the wake of last week’s deadly school shooting in Florida.

The demonstrations took place Wednesday at schools from Maine to Arizona. Some lasted 17 minutes in honor of the 17 people killed one week earlier at Marjory Stoneman Douglas High School in Parkland.

Students at many of the protests called for stronger gun control and said they’re taking action to protect schools because Congress hasn’t.

Hundreds of students in Maryland left class to rally outside the U.S. Capitol, some carrying signs saying “Make Our Schools Safer.”

Students at Simon Kenton High School near Cincinnati marched around their school chanting “Never again.”

More walkouts are already being planned for March 14, a month after the Florida shooting.