San Francisco ? The National Rifle Assn. sued Wednesday to overturn an ordinance voters overwhelmingly approved a day earlier that bans handgun possession and sales of firearms in the city.

A state appeals court in 1982 nullified a similar gun ban largely on grounds that the city cannot enact an ordinance that conflicts with state law, which allows for the sale and possession of handguns and ammunition.

The NRA filed its lawsuit Wednesday asking the same court, the 1st District Court of Appeal, to nullify the ordinance, which demands that city residents surrender their handguns by April.

The NRA contends the new ordinance unfairly puts San Francisco residents at a disadvantage by denying them the means to protect themselves. The measure does not bar nonresidents from possessing handguns within city limits.