WASHINGTON — Fresh off a string of election victories, former New York City mayor Michael Bloomberg's gun-control group is gearing up for a "significant" legislative push in more than a dozen states to curb gun violence, its leaders say.

First up: Nevada, where election officials could certify this week that the group and its allies have collected enough signatures for a 2016 ballot initiative that would impose stricter background checks on people buying firearms from private sellers and at gun shows. Bloomberg's Everytown for Gun Safety also is weighing similar background-check initiatives in Arizona and Maine.

It also plans to back legislation in several states that would either expand background checks for gun purchasers, remove guns from the hands of domestic abusers or give family members the power to seek court orders to temporarily confiscate firearms from people they fear may commit gun violence — modeled on a "gun-violence restraining order" law signed by California Gov. Jerry Brown earlier this fall following a shooting rampage in Santa Barbara.

The California law, the first of its kind, is one of a slew of little-noticed victories gun-control groups have scored at the state level — even as Congress has rebuffed expanding background checks on all commercial sales of guns or restrictions on high-capacity magazines.

Six states have enacted measures that make it harder for people convicted of domestic violence to have firearms. In Colorado last month, two legislative seats lost in the state's historic 2013 recall election over the state's stricter gun-control laws moved back to Democratic control. One of the victors, Michael Merrifield, once worked for a Bloomberg gun-control group.