WASHINGTON — The House voted on Wednesday to require background checks for all gun purchasers, including those at gun shows and on the internet — the first significant gun control bill to clear the chamber in a quarter of a century.
The 240-to-190 vote is the first of two gun control measures expected to be put to House lawmakers this week. However, House Republicans prevailed in adding a provision that would require the F.B.I. to alert Immigration and Customs Enforcement if an undocumented immigrant tried to obtain a firearm. Twenty-six Democrats, primarily from moderate or Republican-leaning districts, broke party lines to support the measure.
Still, the passage of the bill highlights a significant shift in political appetite to pursue aggressive restrictions on firearm sales after last year’s massacre at Marjory Stoneman Douglas High School in Parkland, Fla., which led to a wave of student-led activism.
The House had not taken up expansive gun control measures since 1994.
“Finally, we have done more than thoughts and prayers. Finally, we have taken a vote to expand background checks and help save lives,” said Representative Mike Thompson, Democrat of California, who leads the congressional Gun Violence Prevention Task Force.
“For six long years, we worked on this issue and the previous majority would not even let us have a hearing, let alone a vote to expand background checks,” Mr. Thompson said. “Today is a new day and the show of support on both sides of the aisle for this important legislation is humbling.”
More than 100 student activists, gun violence survivors and advocates looked on from the House gallery as lawmakers advanced Mr. Thompson’s legislation, the Bipartisan Background Checks Act. It seeks to close loopholes that allow individuals to buy firearms on the internet or at gun shows without having to pass a background check.
The Democrat-led House is expected to continue its drive and pass legislation on Thursday that would extend the amount of time the F.B.I. has to conduct background checks of gun purchasers, to 10 business days from three. It is an attempt to close the so-called Charleston loophole, which allowed Dylann Roof, the white supremacist who killed nine people in 2015 at a historically black church in Charleston, S.C., to buy a handgun even though he should have been barred from purchasing the weapon.
It is “unlikely” that either measure will be taken up in the Republican-controlled Senate, Senator John Thune of South Dakota, the No. 3 Republican, said on Tuesday. House Republicans have flatly condemned both pieces of legislation, arguing the measures would be both ineffective and infringe on law-abiding citizens’ rights.
The House bill that was approved on Wednesday “is taking the fears and concerns of a nation over gun violence and perpetrating a fraud on them,” said Representative Doug Collins of Georgia, the top Republican on the Judiciary Committee. “The reality is nothing in this bill would have stopped Parkland, or stopped any of the other violence we have seen.”
Gunmen at the center of a number of high-profile mass shootings passed background checks and legally purchased the firearms they used. But gun control activists have praised both background check measures as a critical first step in a broader drive to reduce gun violence.
“America’s current background check system is like having two types of security lines at the airport: one for people who are willing to be screened, and one you can waltz right through carrying whatever you want,” said John Feinblatt, the president of Everytown for Gun Safety. “We applaud the House for moving so quickly.”