Thousands of protesters surged onto the streets of downtown Portland Saturday in a national day of action to demand stricter gun control and an end to mass shootings.

The demonstration was one of hundreds of March for Our Lives events held in the U.S. and other parts of the world, organized in the aftermath of a shooting that killed 17 students and teachers last month in a Parkland, Florida, high school.

Outraged Portland protesters said they were tired of seeing people gunned down in public places because elected officials would not tighten gun laws and outlaw military-style rifles.

“It is up to our generation – the mass-shooting generation – to make the change we need,” 20-year-old protest organizer Hamdia Ahmed told a crowd packed into the street in front of Portland City Hall. “We have a right to go to school without being afraid.”

Portland police closed an eight-block section of Congress Street from Congress Square to City Hall to allow the march. Protesters represented every age group, from toddlers on shoulders and in strollers to octogenarians in wheelchairs and walkers, along with dozens of dogs.

Organizers expected 1,700 people to show up and another 3,500 people expressed interest in the demonstration, according to their permit to use city property. Ahmed, in a phone interview Saturday, estimated that between 4,000 and 5,000 people were there. Jessica Grondin, the city’s spokeswoman, put the number at 5,000, “maybe a little more.”

“This was a great turnout,” she said.

“Even if it was just a few hundred, that would have been good too,” Ahmed added. “As long as there are people supporting this, that is all that matters. If we have more people, it is that much more powerful.”

As demonstrators made their way down Congress Street, they chanted “Enough is enough!” “No more guns!” and “Keep kids safe!”

Kristen Deiley and Mackenzie Farnham, both 15 and students at South Portland High School, were among hundreds of students who took part in the march.

The two friends also participated in a student walkout this month to protest gun violence, and Deily hoped the public show of support for gun control will make a difference.

“It has to do something with the amount of people speaking out,” Deiley said as protesters gathered Saturday morning in Congress Square Park. “We won’t be silenced.”

Amber Lewis, 20, a student at Southern Maine Community College, held a sign that denounced “thoughts and prayers” – a reference to a phrase favored by public officials in response to tragedies such as mass shootings – next to a crossed-out picture of a military-style rifle.

“Every day we look on Facebook and we see people say, ‘We’re praying for you,’ ” Lewis said. “Thoughts and prayers don’t do a thing. That’s all looks.”

Many signs, like that of Lewis, had large, crossed-out pictures of military-style weapons and slogans such “Arms should be for hugging,” “Keep calm and ban assault weapons,” and “Make America safe again.”

Jack Matheson, 59, of Portland came to the protest with eight members of his family, including his 18-year-old son, Theo.

“I’m fed up with the violence, our whole family is fed up with it,” Matheson said. While the shooting at Marjory Stoneman Douglas High School in Parkland on Feb. 14 sparked the current push for tighter gun laws, Matheson said the line had been crossed long ago.

“It should have stopped at Sandy Hook. That wasn’t enough?” he said, referring to the 2012 shooting at Sandy Hook Elementary School in Newtown, Connecticut, that killed 26 people, including many 6- and 7-year-old children.

Although he is a gun owner, Matheson said it is too easy to buy a firearm. He would like to raise the legal age to buy a gun to 21 and tighten background checks.

“I’d like to see a much stronger process for anyone buying a weapon,” he said.

Demonstrators’ anger at politicians, particularly Republicans, and the National Rifle Association was on full display.

“Despite hearing children beg for change, many say, ‘This is not the time,’ ” Kerrigan Stevens, a 15-year old student at Gray-New Gloucester High School, said in an speech to protesters. “We need to vote in November for candidates who will change laws and protect us,”

Cries of “vote them out” surged through the crowds, and many protesters held signs denouncing the NRA and accusing politicians of selling out to the gun lobby while people were gunned down.

“The government is doing nothing. They allude that they are going to make changes after one of these shootings, and then they do nothing. It has been going on for years,” said Mike Metcalfe, 47, from Kennebunkport.

Metcalfe, who came to the rally with his wife, Jenny, and teenage daughter, said he wanted a ban on assault weapons and high-capacity magazines.

Jenny Metcalfe, 48, said she was encouraged by the energy and passion of young organizers and thought it made the possibility of gun control closer than before.

“I think, especially because of the youth, it is going to change,” she said.

Just outside the crowd of people around City Hall, Jason Herrick, 18, and Sophie Mitchell, 17, both high school students from Blue Hill, were registering to vote for the first time – at a table set up by the League of Women Voters.

Mitchell said she didn’t exactly know how she would vote in the upcoming election, but gun control was a big motivator for her.

“Definitely the gun laws,” she said. “That has been especially on my mind lately.”

A crowd assembled at the steps of City Hall after the march and spilled out into the street, filling nearly a full city block.

Eight student speakers, from middle school to college, addressed the crowd, demanding gun control measures and an electoral wave in November to remove politicians who received NRA campaign contributions.

“The fact of the matter is, when there are more guns, more people die,” said Shaman Kirkland, a sophomore at the University of Southern Maine.

“The days of the NRA are numbered in the state of Maine, and they are over in the city of Portland.”