The first sign that New York City Mayor Michael Bloomberg’s $12 million gun control ad campaign targeting senators might not go as planned?

One of 2014’s most vulnerable Democratic incumbents, Sen. Mark Pryor of Arkansas, is using the media blitz to demonstrate political space between him and Bloomberg.

“I’ve gotten a lot of questions about NYC Mayor gun ad. My response? I don’t take gun advice from the Mayor of NYC. I listen to Arkansans,” Pryor tweeted Monday afternoon.

Bloomberg announced over the weekend that he plans to fund advertisements in 13 states during the Easter recess targeting vulnerable Democratic senators, including Pryor, and Republicans representing competitive states. The goal, according to The New York Times, is to pressure senators he believes could be persuaded to support universal background checks for firearm sales.

Democrats and Republicans view Pryor as vulnerable in 2014, although he has not attracted a top-tier GOP opponent. National conservatives are recruiting freshman Rep. Tom Cotton to challenge him.

Bloomberg has been the country’s most vocal — and well-funded — voice pushing for Congress to pass stricter gun control measures.

Last month, Bloomberg spent more than $2 million to boost Robin Kelly, a Democrat running in the special election for Illinois’ 2nd District, who supported additional gun control measures. Kelly easily won the primary, and now she is expected to win the general election next month in the heavily Democratic district.