Former state representative Robin Kelly. (M. Spencer Green/AP)

In a victory for gun-control advocates led by New York City Mayor Michael Bloomberg, former state representative Robin Kelly won the Democratic nomination in Illinois' 2nd District special election Tuesday, defeating former congresswoman Debbie Halvorson, whose positions on guns had come under consistent attack from opponents.

The Associated Press called the race for Kelly, who led Halvorson 56 percent to 20 percent, with six in ten precincts reporting. Fourteen other Democrats competed for the nomination.