(WASHINGTON) — President Joe Biden was briefly interrupted by a parent whose son was killed in a mass school shooting as he hosted hundreds impacted by gun violence on the White House South Lawn Monday to tout the first major bipartisan gun legislation to pass through Congress in nearly 30 years.

Before he spoke, Dr. Roy Guerrero, a Uvalde pediatrician who treated the victims of the Robb Elementary School mass shooting, and Garnell Whitfield, Jr., son of the oldest Buffalo massacre victim Ruth Whitfield, first offered brief remarks to introduce Biden and Vice President Kamala Harris.

“The dried white roses and the sun-bleached teddy bears have been taken away and stored. What remains is a hollow feeling in our gut,” Guerrero said.

“It’s been tough being a pediatrician in a community where children do not want to return to school, and parents don’t want to send them there with the fear of a future attack,” he added. “I spend half my days convincing kids that no one is coming for them and that they are safe knowing that they’re safe — but how do I say that knowing that the very weapons used in the attack are still freely available? Let this only be the start of the movement towards the banning of assault weapons.”

Whitfield read the names of the victims in the Buffalo shooting, which took the life of his 86-year-old mother, and while he praised Biden and Harris for their work to mitigate gun violence said, “We know that this is only the first step.”

Biden signed the Bipartisan Safer Communities Act into law last month, but the signing was overshadowed since it came one day after the Supreme Court released its decision to overturn Roe v. Wade. Monday provided the president a new opportunity to take a victory lap — but it also came one week after another mass shooting at a July Fourth parade in Highland Park, Illinois, left seven dead and dozens wounded.

About one week to the hour of the Highland Park shooting, Biden took the podium on the South Lawn, wearing a ribbon on his lapel to honor gun violence victims.

Not long after he started speaking, Manuel Oliver, whose 17-year-old son Joaquin was killed in the Parkland mass shooting, interrupted Biden’s remarks in an apparent protest. Oliver has publicly criticized the legislation.

“We have to do more than that!” Oliver shouted. “I’ve been trying to tell you this for years!”

Biden said, “Let him talk,” before continuing with his prepared remarks as Oliver was escorted away by a staffer.

Later, speaking to reporters, Oliver defended his decision to interrupt Biden — taking issue with the White House making this bipartisan achievement into a “celebration” — and pointing to the community of Uvalde still mourning the loss of the 19 children and two teachers who were killed.

“The word celebration has been used in the wrong way. We were invited to Uvalde this week. Mothers are still crying in Uvalde,” he said. “And meanwhile, we, some way, by being here, clapping and standing ovation, these types of bills, which by the way I welcome, because it will save some lives, while we do that, other people are just getting shot. We cannot accept that.”

Biden named the leaders of the bipartisan Senate negotiations which crafted the legislation, including Sens. Kyrsten Sinema, Chrisy Murphy, and Thom Tillis, and joked that he hoped he doesn’t get Republican John Cornyn of Texas “in trouble” for praising him, too. Biden and Cornyn shook hands after his remarks.

President Biden said none of the actions he’s calling for infringe on Second Amendment rights, even repeating his support for the Second Amendment, but that “we can’t just stand by” when guns are the “number one killer of children in the United States.”

“Guns are the number one killer of children in the United States of America … And over the last two decades more high school children have died from gunshots and on-duty police officers on active duty military combined,” Biden said. “We can’t let it happen any longer.”

“With rights come responsibilities. Yes, there’s a right to bear arms. But we also have a right to live freely, without fear for our lives in a grocery store, in a classroom, in a playground, and a house of worship, in a store, at a workplace, a nightclub, a festival, in our neighborhoods, in our streets,” he added. “The right to bear arms is not an absolute right that dominates all others.”

Gun violence survivors and family members of victims of recent mass shootings in Uvalde, Texas, and Buffalo, New York, attended, as well as survivors and family members from the Columbine, Sandy Hook and Parkland mass shootings, among others. But some gun safety advocates lament that it doesn’t go far enough.

Ahead of Monday’s event, Biden asked Americans in a tweet to text him their stories of how gun violence has impacted their communities, looking to tout how the new law will help stop similar violence.

The Bipartisan Safer Communities Act includes $13 billion in new spending for mental health programs and for securing schools. It also makes background checks stricter for gun buyers under 21, helps to close the so-called boyfriend loophole to restrict domestic violence offenders from purchasing guns, and incentivizes red flag laws to remove firearms from people deemed to be a danger to themselves or others.

But it doesn’t go as far as many wanted, including Biden, lacking measures such as universal background checks and a ban on assault weapons and high-capacity magazines.

As the president marked progress on gun reform Monday, he also called on Congress to act further.

He called for legislation that would ban assault weapons and high-capacity magazines, strengthen background checks and enact safe storage laws.

“We’re living in a country awash in weapons of war. Weapons that were designed to hunt are not being used; the weapons designed that they’re purchasing are designed as weapons of war, to take out an enemy,” he said. “What is the rationale for these weapons outside war zones?”

The president’s ask for more congressional action comes as the Senate returns from its July Fourth recess Monday. Notably, Senate Majority Leader Chuck Schumer was not at Biden’s event because he is isolated with COVID-19.

ABC News’ Justin Gomez and Alexandra Hutzler contributed to this report.

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