SAN FRANCISCO (AP) — Bus shelter advertisements featuring a woman holding a shotgun and promoting a gun rights conference have popped up around San Francisco.

The group behind the posters — which ask "Can you afford to be unarmed?" — is challenging the city transit agency's policy of banning any bus and train ads that "appear to promote the use of firearms."

San Francisco's Metropolitan Transportation Agency spokesman Paul Rose says officials allowed the Second Amendment Foundation to put up the posters while officials reconsider the ban, enacted several years ago.

Rose says the issue came up after a recent Supreme Court decision limiting the regulation of firearms by state and local authorities.