San Francisco, Sep 10 (IANS): The US National Rifle Association (NRA) has sued San Francisco for declaring the gun-rights advocate as a "domestic terrorist organization".

The NRA brought the lawsuit against San Francisco and its elected officials in US District Court for the Northern District of California on Monday by accusing the city of violating the rights of the group's members protected by the First Amendment of the US Constitution, Xinhua news agency.

The San Francisco Board of Supervisors passed a resolution last week declaring the NRA a "domestic terrorist organization" in the wake of mass shootings in the past months across the country that have killed several people.

The resolution was introduced by Supervisor Catherine Stefani following the shooting epidemic, particularly the Gilroy Garlic Festival shooting in late July in Northern California, in which three innocent people were killed, including a six-year-old boy and a 13-year-old girl.

According to the court file published by the NRA on social media on Monday, the pro-gun group called the San Francisco resolution "unconstitutional," saying that its "terrorist designation" is a frivolous insult.