Republicans and a veterans group have pounced on a comment by Arkansas Democrat Sen. Mark Pryor that his Republican opponent feels a "sense of entitlement" because he served in the military.

Pryor, one of the country's most vulnerable Democrats, is being challenged by Rep. Tom Cotton, an Army veteran who earned a Bronze Star Medal, Combat Infantry Badge, and Ranger Tab during deployments in Iraq and Afghanistan.

"This is a sad display of arrogance from a career politician who has been seeking office for more than two decades and an insult to everyone who has served," said David Ray, spokesman for Cotton's campaign.

The Arkansas Senate race is part of ABC News' 14 for 14 coverage. Click here for a snapshot of the race.

"To suggest, as Senator Pryor has, that military service is not a qualification to run for office is an affront to every man and woman who has put on the uniform to serve this country," Doyle Webb, chairman of the Republican Party of Arkansas, said.

"Senator Pryor should be ashamed of himself. He revealed a shocking disdain toward veterans when he dismissed the military service of his opponent Tom Cotton and said it doesn't qualify him to serve in the Senate," said Garry Stubblefield, a former Navy SEAL and chairman of Special Operations for America, an anti-Democratic Party super Pac. "This period of Tom Cotton's life has uniquely qualified him because it adds a much-needed perspective on military and foreign policy to the United States Senate from the viewpoint of someone who has actually worn the country's uniform."

Pryor, who is seeking a third term in the Senate, is facing one of the toughest re-election races in this year's mid-term election against Cotton, who has the backing of both the establishment and Tea Party groups.

In discussing his opponent Pryor recently told NBC News, ""There's a lot of people in the Senate that didn't serve in the military. Obviously in the Senate we have all types of different people, all kinds of different folks that have come from all types of different backgrounds. And I think that's part of that sense of entitlement that he gives off is that, almost like, I served my country, let me into the Senate. But that's not how it works in Arkansas."

Pryor also said he has "total respect" for Cotton's two tours of duty in Iraq and Afghanistan, saying "I would never criticize anyone for serving our country, and I say thank you."

Erik Dorey, a spokesman for Pryor's campaign, said today, "Of course Mark is grateful for Congressman Cotton's service, but this campaign is about two very different records in Congress and it's Cotton's irresponsible votes against Medicare, Social Security and affordable student loans that matter most to Arkansas voters."