WASHINGTON (Reuters) — President Joe Biden is expected to start rolling out executive actions regulating guns as soon as Thursday, according to a person familiar with the matter.

The responses are expected to include a presidential declaration that could ultimately require people who buy untraceable, self-assembled “ghost guns” to undergo a background check, the person told Reuters.

The measure is one of several the administration has been working on for months to try to limit gun violence but without starting a legal battle that could lead to courts quickly dismantling the policies.

The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives has said more than 30% of the illegal weapons it has confiscated in some areas of California are “ghost guns” but they are not currently regulated as firearms that require background checks.

Mass shootings last month in Georgia and Colorado have put pressure on the White House to act, as swift legislation is not likely through Congress.

Gun control activists have been invited to an event at the White House about the matter on Thursday, according to a different person familiar with the matter.

White House press secretary Jen Psaki declined to comment on which policies Biden would sign but said Biden would discuss the issue on Thursday.

“I don’t have anything to preview,” she said. “I can convey that I expect the president will have more to say tomorrow.”

The Department of Justice did not respond to a request for comment.

Additional reporting by Sarah Lynch Editing by Chris Reese and Howard Goller.

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