The National Rifle Association filed a lawsuit against San Francisco on Monday after the city declared the gun-rights group a "domestic terrorist organisation" last week.
"This action is an assault on all advocacy organisations across the country", NRA's attorney William A. Brewer III said, stressing that the group is protected by the First Amendment. "There can be no place in our society for this manner of behavior by government officials".
According to Supervisor Catherine Stefani, San Franciso lawmakers decided to adopt the legislation in response to a shooting at the Gilroy Garlic Festival in July that claimed the lives of four people, including the attacker.
In the meantime, the NRA has also been targeted by attorney generals in New York and Washington, D.C., as the authorities investigate possible violations of the organisation's non-profit status. The association has stated that politicians are seeking to politicise the recent tragedies across the country in order to demonise the NRA and push gun control laws that violate the US Constitution.