WASHINGTON — A bipartisan group of senators on Sunday announced it had reached a framework for enacting modest gun restrictions while beefing up school security and enhancing mental health treatment 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 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.”

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 the House last week.

The framework includes investments in mental health care and school safety, as well as resources for states to create and administer laws to help ensure deadly weapons are kept away from individuals a court has determined to be a significant danger to themselves or others. It also adds an enhanced review process for firearm purchasers under the age of 21.

“Families are scared, and it is our duty to come together and get something done that will help restore their sense of safety and security in their communities,” according to a joint statement issued by Murphy, Cornyn and 18 other senators. “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.”

Although Democrats have pressed for gun legislation in the wake of prior mass shootings, the slaughter last month of 19 fourth graders and two teachers at an elementary school in Uvalde, Texas, prompted a more focused response on Capitol Hill. Instead of demanding bans on assault rifles or other policy that would have prompted rebuke from Republicans, they opened the door to smaller-scale reforms. Republicans, jolted by the deaths in Uvalde, signaled they would come to the table.

Senate Majority Leader Charles E. Schumer praised the agreement in a statement as “a good first step” for Congress to end “persistent inaction” on the nation’s gun violence epidemic.

“Once the text of this agreement is finalized, I will put this bill on the floor as soon as possible so that the Senate can act quickly to advance gun-safety legislation,” said Schumer, who noted that Congress is poised “to take meaningful action to address gun violence” for the first time in nearly 30 years.

Biden in a statement lamented that Congress had not done “everything that I think is needed” but nevertheless hailed the proposal, saying it would be “the most significant gun safety legislation to pass Congress in decades.”

“With bipartisan support, there are no excuses for delay, and no reason why it should not quickly move through the Senate and the House,” Biden said. “Each day that passes, more children are killed in this country: the sooner it comes to my desk, the sooner I can sign it, and the sooner we can use these measures to save lives.”