WASHINGTON — Republican leaders rebuffed calls for major changes to US gun laws Tuesday following the mass shooting at a Florida high school, as students braced for their emotional return to the campus where 14 classmates and three staff were murdered.

Student survivors of the Valentine’s Day assault met with members of Congress to urge curbs on firearm sales but found little enthusiasm for legislative action beyond closing gaps in a national background check system.

President Donald Trump has called for stronger background checks in the wake of the shooting, and the White House said he "still supports" raising the minimum age from 18 to 21 for some gun purchases, a policy opposed by the National Rifle Association, America’s powerful gun lobby group.

Democrats hailed the students as an inspiration. But even with polls showing overwhelming public support for stricter gun laws, it would be a steep climb to achieve dramatic changes to gun laws in a Republican-dominated Congress.

Turning to the specifics of the Florida tragedy, Republicans put the blame on a "colossal breakdown" of law enforcement rather than the easy availability of assault rifles.

"Let me just say we shouldn’t be banning guns for law-abiding citizens, we should be focusing on making sure citizens who should not get guns in the first place don’t get those guns," House Speaker Paul Ryan told reporters.

Ryan and other Republican leaders until now have largely been absent from the debate that has raged since the assault in Parkland, Florida, by a troubled 19-year-old armed with a semi-automatic rifle.

The speaker met with students from Marjory Stoneman Douglas High School, describing them afterwards as "smart and passionate" and saying that "we had an important discussion about how to keep our kids and our schools safe."

But in his remarks to reporters, he blamed the rampage on the failure of local authorities to heed numerous warnings about the shooter, Nikolas Cruz, a former student at the school, rather than lax US gun laws that have been sharply criticized by some survivors.

’Full debate’

"There was a colossal breakdown in the system locally," Ryan said, citing lapses by the FBI and a deputy sheriff accused of failing to act when shooting broke out at the school.

Ryan’s argument echoed that of Trump, who asserted Monday that he would have charged into the school after the shooter, even without a gun.

Trump was scheduled to meet with a bipartisan group of lawmakers Wednesday to address gun laws.

He has pushed for arming teachers as a first line of defence, an approach favoured by the NRA but widely criticised by teachers themselves as an impractical and unreasonable burden on them.

Trump also has called for building more mental hospitals, a ban on devices known as "bump stocks" that allow a semi-automatic weapon to be fired much more rapidly, and better background checks to keep guns out of the hands of "sickos."

A bipartisan "Fix NICS" bill currently before Congress would step up state and federal agency reporting to a national database of offenses that would bar an individual from purchasing a firearm, but Democrats say that is insufficient.

"We want full debate, not just on Fix NICS but on legislation that would do the job," said Senate Minority Leader Chuck Schumer, who also met with the student survivors.

’We are family’

In Parkland, a community overcome with grief was preparing for the resumption of classes, including student Jenna Korsten, who was at the school when the shooting erupted but escaped unhurt.

"I’m going to be strong," Korsten, 17, told AFP near a makeshift memorial adorned with flowers and anti-gun posters, and marked by 17 white crosses.

"I’m a little nervous, but we have to be strong in these kind of situations because we are family and we are all in this together."

Florida’s legislature is weighing whether to raise the minimum age for gun purchases to 21, along with imposing a three-day waiting period, as part of a package of measures sponsored by the state’s Republican governor.

An assault weapons ban is not part of the package.

With the NRA under fire in some quarters for its opposition to far-reaching reforms, several corporations including Delta Air Lines have abandoned their ties with the pro-gun group.

But that move prompted a backlash in the state of Georgia, where Lieutenant Governor Casey Cagle threatened to "kill" a proposed tax cut for Delta -- whose main hub is Atlanta -- unless it reinstates its NRA discount program.

"Corporations cannot attack conservatives and expect us not to fight back," Cagle tweeted. — AFP