WASHINGTON — A bipartisan group of senators on Sunday announced it had reached a framework for enacting modest gun restrictions in response to a recent spate of mass shootings that included a massacre at a Texas elementary school.

If enacted and signed by President Joe Biden, the measure would become the most significant piece of firearms legislation produced by Congress in nearly three decades. The group of 20 senators, led by Chris Murphy, D-Conn., and John Cornyn, R-Texas, announced Sunday that they struck a deal “to protect America’s children, keep our schools safe, and reduce the threat of violence across the country.”

Although the proposal falls far short of the gun safety reforms Biden has lobbied Congress to pass and is far less sweeping than the comprehensive package that advanced in the House last week, it garnered the immediate support of anti-gun groups and the White House.

Here are some of the things the framework would do:

–It would create an enhanced review process for firearm purchasers under the age of 21, including a pause to conduct a background check. Senators working on the proposal have focused considerable attention on the 18- to 21-year-old population, particularly those who showed signs of violence or mental health struggles as a juvenile but are able to purchase a gun at age 18 because their juvenile records are sealed.

–It would require a background check for these purchasers, including a pause if more time is needed for investigators to dig through records. The suspects in recent mass shootings in Buffalo, New York; Uvalde, Texas; and Parkland, Florida, were between 18 and 19 years old.

–A third significant provision of the deal includes closing the so-called “boyfriend” loophole. It would prohibit anyone convicted of abuse against a spouse or domestic partner from buying a gun, a notable victory for activists against domestic violence.

–The proposal would also crack down on gun trafficking and straw purchases.

–The framework would create incentives for states to create “red flag” laws, such as the one in Oregon that allow weapons to be temporarily taken away from people who show a risk of violence against themselves or others.

— And it would beef up school security and mental health care programs.

“Our plan increases needed mental health resources, improves school safety and support for students, and helps ensure dangerous criminals and those who are adjudicated as mentally ill can’t purchase weapons. Most importantly, our plan saves lives while also protecting the constitutional rights of law-abiding Americans,” Murphy, Cornyn and 18 other senators said in a joint statement.

The agreement has the support of 10 Republican senators. If all 10 remain on board and join with all 50 members of the Democratic majority — including the two independents who caucus with them — the measure could overcome a filibuster.

The bipartisan group includes Murphy, Cornyn, Thom Tillis, R-N.C., Kyrsten Sinema, D-Ariz., Richard Blumenthal, D-Conn., Roy Blunt, R-Mo., Cory Booker, D-N.J., Richard Burr, R-N.C., Bill Cassidy, R-La., Susan Collins, R-Maine, Chris Coons, D-Del., Lindsey Graham, R-S.C., Martin Heinrich, D-N.M., Mark Kelly, D-Ariz., Angus King, I-Maine, Joe Manchin, D-W.Va., Rob Portman, R-Ohio, Mitt Romney, R-Utah, Debbie Stabenow, D-Mich., and Pat Toomey, R-Pa.

The National Rifle Association said it would withhold response until the full bill text is released. But the group’s Twitter account said it “will continue to oppose any effort to insert gun control policies, initiatives that override constitutional due process protections & efforts to deprive law-abiding citizens of their fundamental right to protect themselves/loved ones into this or any other legislation.”