President Trump said Monday ”things are moving rapidly” when it comes to raising the minimum age for buying certain guns, but said he is letting the issue play out in the courts before taking action himself.

The president tweeted that on “18 to 21 Age Limits,” he is “watching court cases and rulings before acting.”

“States are making this decision,” Trump added. “Things are moving rapidly on this, but not much political support (to put it mildly).”

The National Rifle Association on Friday filed a federal lawsuit over gun control legislation Florida Gov. Rick Scott has signed, saying it violates the Second Amendment by raising the age to buy guns in the state from 18 to 21.

Licensed firearm dealers under federal law cannot sell handguns to people under 21 and cannot sell long guns to people under 18. Trump has suggested he supports raising the age for long guns to 21.

But when the White House announced a series of recommendations Sunday night meant to stop school shootings, it did not include a proposal to raise the minimum age to buy long guns.

WHITE HOUSE ANNOUNCES GUN SAFETY RECOMMENDATIONS

The proposals, though, include a full audit and review of the FBI tip line after warnings about a student who killed 17 people at a Florida high school last month were not acted upon.

The administration reaffirmed Trump's support for a congressional measure, known as Fix NICS, that helps local officials improve efforts to enter data into the National Instant Criminal Background Check System and the congressional STOP School Violence Act to improve school security and provide some funding for such efforts.

“Very strong improvement and strengthening of background checks will be fully backed by White House,” Trump tweeted Monday. “Legislation moving forward. Bump Stocks will soon be out. Highly trained expert teachers will be allowed to conceal carry, subject to State Law. Armed guards OK, deterrent!”

The president also reiterated his opposition to schools being designated gun-free, calling for more armed security.

“If schools are mandated to be gun free zones, violence and danger are given an open invitation to enter,” Trump said. “Almost all school shootings are in gun free zones. Cowards will only go where there is no deterrent!”

The recommendations were announced nearly a month after the mass shooting at Marjory Stoneman Douglas High School in Parkland, Fla.

Fox News' Samuel Chamberlain and Joseph Weber and The Associated Press contributed to this report.