Updated 6:05 p.m. ET, 4/7/2014
(CNN) – Two leading fiscal conservative groups are going after Thad Cochran, one of the most vulnerable Republican senators up for re-election.
Club for Growth and Senate Conservatives Action announced Monday they would each begin airing television ads against the Mississippi incumbent.
And Cochran's team is hitting back with an ad of their own, slamming GOP challenger Chris McDaniel for his views on government assistance programs and post-Hurricane Katrina disaster relief in the state. And Cochran is also getting assistance from an outside group as the ad wars in the Mississippi GOP Senate primary heat up.
The Club for Growth ad criticizes the longtime Mississippi senator over votes on fiscal issues, tying the incumbent to past presidents' support for increasing taxes and the federal debt.
"1970s - Thad Cochran votes with Jimmy Carter to massively expand federal control of education. 1990s - Cochran votes for George H. W. Bush's 'read my lips' tax increase," the narrator in the ad said. "Today, Cochran votes with Obama to raise the national debt by trillions. Thad Cochran - five decades in Washington is enough."
The group said it dropped six figures on the ads, which will start airing Tuesday throughout the state.
In addition to support from Club for Growth and Senate Conservatives Action, McDaniel has gained backing from a number of national and local tea party groups, as well as conservative power players like former Alaska Gov. Sarah Palin.
"We can't keep sending liberal Republicans like Thad Cochran to Washington and expect a different result. Thad Cochran has been in Washington too long and it's time for a conservative change," said Chris Chocola, president of Club for Growth.
Senate Conservatives Action also announced Monday a new television commercial pushing Mississippi Republicans to vote for McDaniel.
But the incumbent isn't going down without a fight.
Cochran's re-election team also announced an ad that began airing Monday statewide with "substantial money behind it," according to the campaign.
The ad narrows in on McDaniel's defense of his description of Mississippi as a "welfare state" and his wavering support for post-Hurricane Katrina relief funding.
"Sounds crazy, but Chris McDaniel is backed by powerful interests that Gov. Haley Barbour calls 'out-of-state phonies," the narrator said in the ad.
Cochran spokesman Jordan Russell reiterated McDaniel's substantial outside support, suggesting the former state senator remains an obscure and risky choice for Mississippi voters.
"The choice in this race is clear: Thad Cochran has fought for Mississippi's conservative values his entire life," Russell said.
"Thad has represented Mississippi well, and he's never embarrassed us. The more we find out about Chris McDaniel, the clearer the choice becomes for voters in the June 3 election."
Mississippi Conservatives PAC, a pro-Cochran outside group, is also up with a spot that accuses McDaniel of flip-flopping on the issues.
"Chris McDaniel. He says one thing, His record, says something else," says the narrator in the ad, which has been running on TV in the state for a week. The group has spent some $600,000 to run TV and radio commercials in the primary battle since the end of January.
But as the two candidates gear up for the primary, political handicappers say Cochran, one of six GOP senators facing a primary challenger, is the most likely to get pushed out of Congress by a fellow Republican.
"McDaniel has the best chance of any anti-establishment Senate hopeful to knock off an incumbent, and the defeat of Thad Cochran would send shock waves through both the national media and the Republican Party," said Stuart Rothenberg, editor and publisher of the nonpartisan Rothenberg Political Report.
Cochran announced in December he would run for a seventh term in the Senate, about two months after McDaniel threw his hat in the ring.
CNN Political Editor Paul Steinhauser and CNN's Ashley Killough contributed to this report.