The Democratic Congressional Campaign Committee is putting more than $275,000 into advertising in the First District, according to Democratic sources. surpassing the amount the Republican congressional committee has spent on the race.

The $276,000 ad buy from the DCCC is the latest sign that Democrats are concerned Rep. Tim Walz is facing a serious challenge in southern Minnesota from Republican state Rep. Randy Demmer.

The National Republican Congressional Committee twice injected $168,000 in advertising attacking Walz earlier this month, according to Federal Election Committee filings. The Republican committee also spent $11,500 on survey research in the district last week.

Updated: The NRCC has spent a total of $367,000 in the first district, including ad buys of $168,000 on both Oct. 8 and Oct. 15. The original post incorrectly accounted for only one of the ad buys.

In addition, former U.S. Sen. Norm Coleman's American Action Network, which is spending money against Democrats nationwide, has put $175,000 in advertising into the First District, election reports show.

A poll released last week found Walz with a five-point lead over Demmer, 47-42, which was within the margin of error.

The DCCC ad attacks Demmer on privatizing social security, a topic Walz and Demmer have tussled over in their debates.

From the AP's account of a debate last week:

Watch the ad, which will start running Thursday, below: