In the hottest U.S. Senate race in the country, a surprise cease fire has been declared in the political ad war.

Republican Rep. John Thune is battling Democratic incumbent Sen. Tim Johnson for his South Dakota seat. But as of Monday, the candidates agreed that the battle should stop and only ads that have been paid for by the campaigns themselves will be aired.

"This is the right thing to do, not just for the voters of South Dakota, but for the candidates as well," Thune said in a press statement Monday.

For weeks the Republican and Democratic parties and their various campaign committees have been filling the air with ads attacking the candidates based on their support or opposition to various issues in Congress such as the economic stimulus package.

The race — and its accompanying ad face-off — has been a proxy war between President Bush, who easily carried South Dakota in 2000, and Senate Majority Leader Tom Daschle, who hails from the state.

Johnson is considered one of the most vulnerable incumbent Democrats. Thune is a popular congressman. If Republicans pick up one seat in the fall elections they recapture the Senate majority.

Aides say Thune, who proposed the cease fire, is interested in taking back the race from outside special interests and their large soft money contributions and returning the debate to issues that are important to South Dakota.

The ad ban will remain in effect until Thune and Johnson can meet in person later this week to discuss a permanent ban on all third-party political ads in the 2002 Senate race.

Carl Cameron currently serves as Fox News Channel's (FNC) Washington-based chief political correspondent. He joined FNC in 1996 as a correspondent.