Morgan Kierstead, left, and María Smith, seniors at Portland High School, take part in a protest against school gun violence at City Hall Plaza in Portland on Thursday.

Portland High School and Baxter Academy students staged a walkout and 17-minute silence at City Hall on Thursday in the wake of a recent school shooting that left 17 dead in Florida. The event comes one day after a national walkout, but had been postponed in Portland due to snow-related school cancellations.

Portland High School sophomores Carlos Garcia, left, and Abdulrahim Albasha hold a protest sign while joining fellow students during a walkout and 17-minute silence at City Hall on Thursday. Their sign reads "PHS supports #notonemore" as they join a national protest of gun violence in the wake of the massacre of 17 students at a Florida high school.

Portland Mayor Ethan Strimling, far left, takes a photo of Portland High School and Baxter Academy students who staged a walkout and 17-minute silence at City Hall on Thursday in the wake of a recent school shooting that left 17 dead in Florida.

Students walk out of Portland High School Thursday as part of a protest for more stringent gun laws. The protest was postponed from Wednesday because of snow.

South Portland High School students leave the building during a walkout Thursday morning to remember the lives lost Feb. 14 at a school shooting in Florida and to demand action on gun violence.

Cape Elizabeth High School students gather near Hannaford Field on Thursday to show their support for action on gun violence.

Students rally against gun violence outside South Portland High School Thursday.

Westbrook High School walkout organizers Sandy Cao, Kelly Maguire and Zoe Popovic address fellow students who briefly leave classes Thursday in conjunction with a national walkout effort to urge government leaders to take action to stop mass shootings and gun violence in schools and other public places.