Pro-gun activists plan rallies in 49 states at "high noon" on Saturday (US time) to support the right to own firearms they say is under attack from President Barack Obama's proposals to reduce gun violence.
The rallies, to be held mostly at state capitals, were being organised by a group called Guns Across America that was launched by Texas airline pilot Eric Reed.
The US debate over gun control flared in mid-December when a man killed 20 first graders and six adults in a matter of minutes at an elementary school in Newtown, Connecticut, using an assault rifle.
In the wake of the mass killing, Obama and gun control advocates have begun a push to ban assault weapons. A number of other states have taken up gun legislation and New York, which had among the strictest gun control laws in the country, broadened its ban on assault weapons on Tuesday.
Obama also called for a ban on high-capacity magazines and more stringent background checks for gun purchasers.
Gun control advocates say American civilians have no justifiable need for assault weapons or high-capacity magazines, and they say more background checks will help keep guns out of the hands of criminals.
The reaction has been fierce from gun supporters such as the National Rifle Association, who have long argued that their right to bear arms is enshrined in the Second Amendment to the US Constitution.
Reed, 38, has said after he heard Obama talk about gun control on the day of the Sandy Hook massacre in December that he thought gun owners should send a strong message to lawmakers in Washington.
As of Friday afternoon, the Facebook page for Guns Across America listed more than 18,000 people who say they plan to attend events, and Reed said Alaska was the only state with no organiser for a rally.
Meanwhile, gun-control advocates on Sunday plan to hold a National Gun Prevention Sabbath, where they say 150 houses of worship will call on the faithful to advocate for an "actionable plan to prevent gun violence." People who have lost loved ones to gun violence will display their photographs, organisers said.