President steps back from some of the sweeping changes he had considered

US President Donald Trump backs legislation proposed in Congress aimed at providing more data for the background gun check system. Photo / AP

US President Donald Trump will support a modest set of fixes to gun laws, stepping back from some of the more sweeping changes he had considered after the country's latest mass school shooting, senior officials have told reporters.

Opting for a plan the Administration officials described as "pragmatic", Trump backs legislation proposed in Congress aimed at providing more data for the background check system - a database of people who are not legally allowed to buy guns.

More contentious proposals, such as raising the minimum age for buying guns to 21 from 18, or requiring background checks for guns bought at gun shows or on the internet, will be studied by a commission headed by Education Secretary Betsy DeVos, the officials said.

The Justice Department will also provide an unspecified amount of grants to states that want to train teachers to carry guns in school - an idea already in place in a small number of states, and backed by the National Rifle Association gun rights lobby.

Trump has said he believes armed teachers would deter school shootings and better protect students when they happen.

The President, who championed gun rights during his 2016 campaign, vowed to take action to prevent school shootings after a gunman killed 17 people at a high school in Parkland, Florida, on February 14.

The shooting reignited the national debate over gun control. Students who survived the attack have pressured politicians to crack down on guns, and plan a march in Washington on March 24.

Trump challenged Congress to develop a comprehensive bill during a televised meeting with politicians last month, embracing suggestions to close loopholes for gun buyers seeking to avoid the background check system, raise the age limit for buying rifles, and find ways to temporarily seize guns from people reported to be dangerous.

But his initial enthusiasm for restrictions was not shared by many of his fellow Republicans in Congress, wary of measures that could be viewed by some voters as infringing on their constitutional right to own guns, particularly leading up to the November congressional elections.

So he has embraced a proposal from John Cornyn of Texas, the No. 2 Senate Republican, and Democratic Senator Chris Murphy of Connecticut, which is supported by many but not all Republicans.

- Reuters, AAP