The White House plans to close a loophole that allows thousands of firearms to be sold at gun shows and on the internet without federal background checks.
Approximately 23,000 businesses will be classified as licensed firearms dealers, and their firearm sales will be subject to inspection.
“If you're selling guns primarily for profit, you need a permit,” Attorney General Merrick Garland said.
The Biden administration said it expected a court challenge from gun advocates but was confident it would prevail.
“Every major action the president has taken to reduce gun violence has been challenged,” an administration official said.
“And this practice is frequently upheld in court after court. We are confident that this is legal.”
Garland said the regulation is a “historic step” that will “save lives.” He pointed to federal data showing illegal or black market firearms are increasingly being found at shooting scenes.
Vice President Kamala Harris, who heads the Gun Violence Prevention Agency, said for too long unlicensed gun dealers have “got away with” unverified sales.
The closure of the “firearm display loophole” will take effect 30 days after it is published in the federal register this week.
The White House cited the bipartisan Safer Communities Act of 2022, which clarifies who and what constitutes a gun trafficker, to expand background check requirements.
But a spokesperson for prominent Republican Sen. John Cornyn, who worked on the bipartisan Safe Communities Act, called the move “unconstitutional.”
Cornyn plans to introduce a joint resolution of disapproval under the Congressional Review Act, joined by Republican Sen. Thom Tillis, who helped negotiate passage of the bill.
They argue that the new regulations attempt to “rewrite the law” and are “contrary to the intent of Congress,” according to a copy of the resolution reviewed by the BBC's US partner CBS News.
Approximately 80,000 licensed firearms dealers in the United States already require background checks.
According to the Gun Violence Archive, there were more than 40,000 gun-related deaths in the United States last year.