Bixoli, Mississippi (CNN) - The Republican Senate primary race in Mississippi grew more intense Tuesday with the release of a new political ad, one week before voters head to the polls.
State Sen. Chris McDaniel, who's challenging longtime incumbent Sen. Thad Cochran, put out a new spot responding to the senator's own negative ad last week.
"You've probably seen Thad Cochran's negative attack ads," McDaniel says in the new spot. "Newspapers call them shameless. I call them outrageous."
McDaniel's campaign describes the statewide ad buy as "significant."
The latest Cochran ad links McDaniel to the bizarre story involving a political blogger who allegedly took a picture of Cochran's wife in her nursing home bed for a political video. The blogger, as well as three other men, were arrested and face conspiracy charges.
Cochran's wife suffers from dementia and has lived in a nursing home for 14 years.
"It's the worst," the narrator says in the Cochran ad. The female voice then reads a headline from a recent news article: "Chris McDaniel supporter arrested for illegally photographing Thad Cochran's sick wife."
"Had enough?" the narrators asks.
"Rise up and say no to dirty politics," the narrator continues, urging viewers to support Cochran.
A spokesman for Cochran said the ad is running statewide.
McDaniel has all along stressed that his campaign had no involvement or knowledge in the plot.
"I am appalled by that act, as are the people of Mississippi. That's the bottom line, and that's where it should end," he said in an email blast over the weekend.
McDaniel, who enjoys the backing of many tea party activists, other grassroots conservatives, and some anti-establishment groups, is considered to have the best chance of any of the primary challengers from the right who have been trying to unseat incumbent GOP senators running for re-election this year. The primary race has attracted a lot of attention both in Mississippi and across the country, and has seen a bunch of spending by outside groups.
One of those groups is the Mississippi Conservatives PAC, a pro-Cochran outside group that has been running ads in support of the six-term senator since the beginning of the year. The commercial criticizes McDaniel for having the worst voting record of any current state senator in Mississippi the past four years.
"A state senator who doesn't show up for work. McDaniel has the worst attendance record in the state senate. Absent 118 times. Skipping votes on taxes, debt and spending. McDaniel even skipped an important pro-life to campaign in Washington, causing the amendment to fail by one vote," said the narrator in the spot.
The group says it will spend $300,000 to run the commercial statewide. The ad does not mention the recent scandal involving Cochran's wife.
The U.S. Chamber of Commerce, which tends to support mainstream Republicans, has also run ads in support of Cochran. The Club for Growth and Senate Conservatives Fund, two DC-based anti-establishment groups, have spent big bucks backing McDaniel.
Most of the recent partisan polling in the primary race indicates that Cochran's the front runner for the nomination.