Washington – US President Donald Trump stood accused on Monday of caving in to the US gun lobby one month after the Florida school shooting, as the White House pushed ahead with plans to arm teachers but backpedalled on curbing access to assault rifles.

Under pressure to act after a teenager killed 17 people with a semi-automatic rifle in Parkland, Trump had signalled support for raising from 18 to 21 the federal minimum age for purchasing the powerful weapons.

But a new policy statement focused on Trump's idea of arming teachers, "making sure our schools are safe and secure, just like our airports, stadiums and government buildings".

As for federal age limits on gun purchases, it only said the government would form a special commission on school safety, with Education Secretary Betsy DeVos in charge.

It made no mention of expanding the vetting of firearms buyers to sales online and at gun shows, another idea previously floated by the White House.

However, the policy statement did endorse minor legislation in Congress to improve federal and state databases used for background checks by licensed dealers.

Those moves fell close in line with the position of the National Rifle Association, the powerful gun lobby that fights any gun ownership restrictions.

Trump himself admitted in an earlier tweet that he is not currently pushing age restrictions that could have prevented 19-year-old Nikolas Cruz from buying the powerful AR-15 assault rifle used on February 14 to kill 14 students and three adults at Marjory Stoneman Douglas High School in Parkland, Florida.

"On 18 to 21 Age Limits, watching court cases and rulings before acting. States are making this decision. Things are moving rapidly on this, but not much political support (to put it mildly)," the president wrote.

Trump 'caved to the gun lobby'

Trump's step backwards, after two extraordinary meetings in recent weeks with NRA executives, has critics accusing him of wilting after three of the worst mass shootings in US history scarred his first year in office.

"President Trump has completely caved to the gun lobby," said Democratic Senator Diane Feinstein.

"He backed off his openness toward an assault weapons ban, support for expanded background checks, barring those who exhibit 'red flags' from buying guns and raising the age to buy assault weapons to 21."

Feinstein called the notion of arming teachers an "utterly ridiculous idea that teachers strongly oppose".

The tepid steps lessened the hopes of gun control advocates that Trump would take a stand in the wake of the Parkland shooting.

Robert Spitzer, an expert on the gun rights debate and chair of the political science department at the State University of New York, College at Cortland, foresaw no meaningful reform in the White House announcement.

"His initiative basically amounts to a big nothing," he said of Trump.

Public wants tougher controls

Polls since Parkland shooting show the US public has turned strongly for tougher regulations.

Students from the high school have taken the lead in a national campaign

Read more from our friends at the NRA