Thousands of people have rallied in Washington DC and across the United States in a renewed push for gun control measures.

The high-profile effort to change the laws follows recent mass shootings in Uvalde, Texas, and Buffalo, New York state, which activists say should compel US congress to act.

District of Columbia mayor Muriel Bowser told the second March For Our Lives rally in her city: “Enough is enough.

“I speak as a mayor, a mom, and I speak for millions of Americans and America’s mayors who are demanding that congress do its job. And its job is to protect us, to protect our children from gun violence.”

Speaker after speaker in Washington called on senators, who are seen as a major impediment to legislation, to act or face being voted out of office, especially given the shock to America’s conscience after 19 children and two teachers were killed on May 24 at Robb Elementary School in Uvalde.

David Hogg, a survivor of the 2018 shooting that killed 17 students and staff at Marjory Stoneman Douglas High School in Parkland, Florida, said: “If our government can’t do anything to stop 19 kids from being killed and slaughtered in their own school, and decapitated, it’s time to change who is in government.”

Mr Hogg co-founded the March For Our Lives organisation following the Parkland shooting, with its first rally in Washington not long after the event.

Yolanda King, granddaughter of Martin Luther King Jr, added: “This time is different because this isn’t about politics. It’s about morality. Not right and left, but right and wrong, and that doesn’t just mean thoughts and prayers. That means courage and action.”

At an amphitheatre in Parkland, hundreds of people heard Debra Hixon – whose husband Chris Hixon died in the shooting – say it is “all too easy” for young men to walk into stores and buy weapons in the US.

“Going home to an empty bed and an empty seat at the table is a constant reminder that he is gone,” said Ms Hixon, who now serves as a school board member.

“We weren’t done making memories, sharing dreams and living life together. Gun violence ripped that away from my family.”

US President Joe Biden, who was in California when the Washington rally began, said his message to the demonstrators was “keep marching”, adding that he is “mildly optimistic” about legislative negotiations to address gun violence.

Mr Biden recently delivered an impassioned address to his country in which he called for several steps, including raising the age limit for buying assault-style weapons.

In the Brooklyn borough of New York City, mayor Eric Adams, who campaigned on reining in violence in the nation’s largest city, joined state attorney general Letitia James, who is suing the National Rifle Association, in leading activists on a march toward the Brooklyn Bridge.

“Nothing happens in this country until young people stand up — not politicians,” Ms James said.

Despite rain in the nation’s capital, thousands arrived on the monument grounds well before the rally began, holding up signs, including one that said “Children aren’t replaceable, senators are. Vote.”

A middle school-age girl carried a sign that read: “I want to feel safe at school”.

Organisers hoped the second March For Our Lives rally would draw as many as 50,000 people to the Washington Monument. While that would be far less than the original 2018 march with more than 200,000 people, they focused this time on smaller marches at an estimated 300 locations.

The youth-led movement created after the Parkland shooting successfully pressured the Republican-dominated Florida state government to enact sweeping gun control changes.

The group did not match that at the national level, but has persisted in advocating for gun restrictions since then, as well as participating in voter registration drives.

Survivors of mass shootings and other incidents of gun violence have lobbied legislators and testified on Capitol Hill this week.

Among them was Miah Cerrillo, an 11-year-old girl who survived the shooting at Robb Elementary. She described for legislators how she covered herself with a dead classmate’s blood to avoid being shot.

On Tuesday, actor Matthew McConaughey appeared at the White House to press for gun legislation and made highly personal remarks about the violence in his home town of Uvalde.

The US house of representatives has passed bills to raise the age limit to buy semi-automatic weapons and establish federal “red flag” laws.

But such initiatives have traditionally stalled or been heavily watered down in the senate.

Democratic and Republican senators had hoped to reach an agreement this week on a framework for addressing the issue and held further talks on Friday, but no accord was announced.