Republicans in the US House of Representatives have introduced a gun control measure that would give authorities three days to prove that someone on a terrorism watch list should not be allowed to obtain a firearm.
The measure, due to come up for a vote next week as part of a broader counter-terrorism package, was immediately rejected by Democrats as "toothless" gun legislation that would not protect the public in the aftermath of the June 12 mass shooting at a gay nightclub in Orlando, Florida.
Lawmakers on both sides of the aisle have said that next week's vote would likely undermine prospects for a stronger bipartisan gun control bill that has been backed by a small number of Republicans in both the House and Senate.
The new gun measure surfaced after House Democrats staged a 25-hour sit-in last week to demand action on gun control legislation.
Similar legislation backed by the National Rifle Association has already been rejected by Democrats in the Senate.
House Republican leader Kevin McCarthy said in a statement that the 24-page counter-terrorism bill would help law enforcement prevent future attacks on US soil and "provide a process for individuals being investigated as known or suspected terrorists who attempt to buy a gun to be flagged, delayed, and - if the burden of proof is satisfied - denied their purchase".
The new Republican bill would apply to anyone who has been suspected of violent extremism within the past five years.
The measure requires a court to block a firearm purchase only if there is probable cause to believe the would-be buyer "will commit an act of terrorism" or violates existing prohibitions on undocumented immigrants, fugitives, convicts and people suffering from mental illness.
"This bill is just the latest evidence that House Republicans have become a wholly-owned subsidiary of the NRA," House Democratic leader Nancy Pelosi said in a statement.