President Joe Biden will announce an executive order Tuesday that instructs the Justice Department to increase the number of background checks on gun sales nationwide, according to senior administration officials.

Biden will make the announcement from the site of a January shooting in Monterey Park, Calif., as his calls to have Congress pass additional gun control measures have fizzled. He signed a law last year that was the most significant in decades to address gun violence, and Tuesday’s executive order builds on language in that measure.

Among other policy changes, the order would direct Attorney General Merrick B. Garland to “clarify” when the law considers someone a gun dealer and must register with the federal government, in a way that will bring the country closer to universal background checks, senior administration officials said.

“There are few policy ideas more popular among the American people than universal background checks, but Congress failed to act,” a senior administration official said. The official spoke with reporters on a call Monday on the condition of anonymity under ground rules set by the Biden administration.

The White House does not have an estimate of how many gun sales may be affected by the order, according to senior administration officials, because there are no government statistics about sales by dealers who should be registered and because the final number would depend on Garland’s actions.

“The important message here is that we are going to be increasing the number of background checks, by ensuring that all background checks required by law are conducted,” a senior administration official said.

A fact sheet provided by the White House stated that Biden would direct Garland to clarify the statutory definition of who is “engaged in the business” of selling firearms, which can require sellers to have federal licenses and run background checks.

Senior administration officials said the bipartisan gun violence law passed last year changed the definition of gun dealer, which gave the administration an “opening” to regulate.

The law created grants for state crisis intervention laws and provided several billion dollars in mental health and school security funding. It also closed the so-called “boyfriend loophole” by extending a firearm ban for those convicted of domestic violence to include dating partners as well as spouses, and required more thorough background checks for gun buyers under age 21.

The administration framed Tuesday’s announcement as a major step toward increasing the number of background checks on gun sales. The order would also include a directive to Garland to make sure that dealers who lose or surrender their licenses do not continue to sell firearms.

Separate from the Justice Department provisions, administration officials said the executive order would beef up investigations of firearm thefts during shipping, encourage the Federal Trade Commission to investigate gun marketing to children, and publicize information about extreme risk protection orders and the nation’s ballistics lab.

During his State of the Union address last month, Biden called on Congress to address gun violence, particularly to require background checks on all gun sales, require safe storage of firearms, and ban assault weapons and high-capacity magazines.

However, those proposals are unlikely to advance in the Republican-controlled House, where members have called for votes to scale back enforcement of federal firearms laws, including the Bureau of Alcohol Tobacco, Firearms and Explosives.

The policies announced Tuesday will also likely face challenges in federal court, as have all prominent changes to federal gun regulation. That includes pending challenges to the ATF’s rules on pistol braces and bump stocks.