Washington (CNN) A pro-gun control group will launch a $5 million ad campaign targeting voters in 15 contentious US House races.

Everytown for Gun Safety Action Fund, announced Tuesday its plans to reach voters in several congressional swing districts in a new digital ad campaign titled "Not One More."

The campaign from the group founded by former New York City Mayor Michael Bloomberg will initally focus on 15 congressional districts that the group is working to flip red-to-blue or hold onto in tight races. CNN rates seven of the targeted races as a toss up, seven as lean Democrat and one as likely Republican.

"'Not one more' — three simple words that serve as both a statement of principle and a call to action for the growing gun safety movement," said John Feinblatt, president of Everytown for Gun Safety. "This urgent ad campaign will inspire even more Americans to head to the polls on November 6 and vote for their local gun-sense champions."

The ads including pictures from shootings scenes from will run in congressional districts in California, Colorado, Georgia, Kansas, Minnesota, Nevada, Florida, Michigan, New Jersey, Washington and Virginia. One ad reads, "Not one more high school. Not one more church. Not one more concert, office, campus, newspaper, kindergarten class. Not one more."

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