Washington (CNN) - A large gun advocacy group is hitting its first Democrat in their most recent campaign to increase gun control measures.
Mayors Against Illegal Guns, founded by independent New York City Mayor Michael Bloomberg, announced an ad Friday criticizing Democratic Sen. Mark Pryor for his recent vote against gun legislation in the Senate, including expanding background checks.
A spokesperson for the organization that includes mayors from across the country said they are putting $350,000 into 30-second spot, which features a woman who lost her friend to gun violence.
"I was so disappointed when Mark Pryor voted against comprehensive background checks," Angela Bradford-Barnes says in the spot. "On that vote he let us down. Tell Mark Pryor to take another look at background checks."
Pryor, who also knew the gun victim, said in a statement the ad is politicizing his death by "misleading people into thinking that his bill would have prevented Bill Gwatney's tragic death. The fact is it wouldn't have, which makes Mayor Bloomberg's ad even more disgusting."
The senator pointed to his support for measures that would increase funding for mental health programs and penalties for straw purchases that he said would have prevented his friend's death.
Mayors Against Illegal Guns also sent the father of a Newtown shooting victim to one of Pryor's public events in Arkansas earlier this month.
The Arkansas senator is up for reelection in 2014 and in a vulnerable position. The ad, which the group said will begin airing over the next two weeks, is the latest step by the group to promote additional gun control measures, many of which failed in Congress earlier this year. They have launched ads recently against other Republican senators, including Jeff Flake of Arizona and Kelly Ayotte of New Hampshire for their background check votes.
– CNN's Kevin Bohn and Gabriella Schwarz contributed to this report.