US President Joe Biden has called for Congress to pass gun law reforms, including a ban on assault weapons.
Mr Biden released the statement on Sunday, the third anniversary of the Parkland school shooting in Florida.
"All across our nation, parents, spouses, children, siblings, and friends have known the pain of losing a loved one to gun violence," he said.
In 2018, 17 people at Marjory Stoneman Douglas High School were killed by an ex-student armed with an AR-15 rifle.
Many of the school's teenage survivors went on to become prominent advocates for gun legislation reform.
The right to bear arms is protected by the Second Amendment to the US constitution and is staunchly defended by many conservatives, including ex-president Donald Trump.
In his statement, President Biden also called for the introduction of background checks for all gun sales, a ban on high-capacity magazines, and for an end to legal immunity for gun manufacturers.
"We owe it to all those we've lost and to all those left behind to grieve to make a change," Mr Biden said. "The time to act is now."
In a separate statement, House Speaker Nancy Pelosi said Congress would resurrect background check legislation that had stalled when Republican former President Donald Trump was in office.
"Now, working with the Democratic Senate and Biden-Harris Administration, we will enact these and other life-saving bills and deliver the progress that the Parkland community and the American people deserve and demand," she said.