Harris was meeting with families of the victims and is walking the halls at Marjory Stoneman Douglas High School in Parkland, where the murders happened in a building that is planned to be demolished later this year.

As part of her visit, Harris will call for 29 of the 50 states that have no "red flag" laws laws to pass them and encourage 15 more states that have the laws to start using available federal funds to implement them, according to a White House official.

The laws allow courts to issue "extreme risk protection orders" removing firearms from individuals considered at risk of harming themselves or others.

Six U.S. states both have such laws and are tapping $750 million available under the 2022 Bipartisan Safer Communities Act to implement crisis intervention programs, the official said.

Florida approved a red flag law after the 2018 shooting but has not used the federal funding, according to the official, who spoke on condition of anonymity.

The Parkland shooter, a former student there who was 19 at the time, had been seen for mental health issues. He pleaded guilty and was sentenced to life in prison.

The building where the shooting took place has remained largely unaltered since the 2018 shooting, with bloodstains and bullet holes still visible.

It looms eerily over the rest of the campus behind a chain-link fence, where it can be seen as current students walk to their classes, and serves as a constant reminder of the tragedy.

President Joe Biden has made gun violence a key issue in his 2024 reelection bid and tapped Harris, a former prosecutor, to oversee the effort. Both have traveled across the country to meet with people whose families died in mass shootings.

Some advocates regard the red flag laws as violating their constitutional right to bear arms, while gun safety advocates point to some studies showing the statutes can prevent some deaths.

The United States has the highest level of firearm homicides among high-income countries with populations over 10 million, according to the Institute for Health Metrics and Evaluation at the University of Washington School of Medicine.

Biden, a Democrat, wants Congress to approve a new assault weapons ban and to require background checks for all U.S. gun sales. Each measure will be difficult to pass in a divided Congress. Republican candidate Donald Trump has previously supported red flag laws but opposed broader measures favored by Biden.

(Reporting by Trevor Hunnicutt. Editing by Gerry Doyle and Jonathan Oatis)

By Trevor Hunnicutt