Republican U.S. Senate candidate Pete Hoekstra's campaign has filed a complaint with the Federal Elections Commission over an independent political action committee that's running TV ads attacking him.
Hoekstra's campaign says Prosperity for Michigan acted illegally when it didn't disclose donors in its July 13 quarterly report and then filed an amended version Monday showing hefty donations starting in April.
The group's treasurer didn't return a Tuesday call seeking comment.
Detroit-area business executives who support Republican Clark Durant are funding the PAC. It has spent nearly $500,000 to air ads before the Aug. 7 primary.
A Durant campaign spokesman says Hoekstra is just trying to distract voters from his record.
Hoekstra, Durant and Randy Hekman are competing in the Republican primary. The winner will challenge Democrat Debbie Stabenow in November.