Garnell Whitfield Jr., son of 86-year-old Buffalo, New York, mass shooting victim Ruth Whitfield, told the Washington, D.C., crowd, "We were being naïve to think that it couldn’t happen to us. And until it happened to us, we were sitting on the sidelines."

"Guns by themselves are only one aspect of a much more insidious problem in America," he said, calling out the systems he said radicalize mass gunmen, "filling them with weapons and hate-fueled rhetoric."

"Through their inaction they're giving their tacit approval," he said, demanding the passage of an anti-white supremacy hate crime bill.

The Rev. Denise Walden-Glenn, whose brother died of gun violence in Buffalo, addressed the crowd ahead of Whitfield.

She said she's "working tirelessly to figure out long-term, sustainable solutions" to address gun violence and issues that plague Black and Brown communities across the U.S.

"We need a national government that understands equity," she said. "We are tired of them not valuing us."

She added, "If they don’t give us what we ask for, we will vote them out."

Rep. Ted Deutch, D-Fla., joined a Saturday morning march in Parkland, Florida, home to the 2018 high school mass shooting that killed 17 students and educators.

"In the great struggle to rid our communities of gun violence, the kids will win," he wrote.

Sen. Debbie Stabenow, D-Mich., attended a local rally in Michigan, where a student held a sign reading, "I should be writing my college essay not my will."

President Joe Biden tweeted support for the marches Saturday morning.

"Today, young people around the country once again march with [March For Our Lives] to call on Congress to pass commonsense gun safety legislation supported by the majority of Americans and gun owners," Biden tweeted. "I join them by repeating my call to Congress: do something."

Speakers at Saturday's Washington, D.C., rally will include Garnell Whitfield, son of 86-year-old Buffalo mass shooting victim Ruth Whitfield; David Hogg, a Parkland survivor and March For Our Lives co-founder; and Yolanda King, a 14-year-old granddaughter of Martin Luther King Jr.

Garnell Whitfield said to the Senate Judiciary Committee this week, "I ask every one of you to imagine the faces of your mothers as you look at mine, and ask yourself, 'Is there nothing that we can do?'"

"Because if there is nothing, then respectfully senators, you should yield your positions of authority and influence the others that are willing to lead on this issue. The urgency of the moment demands no less," he said.