WASHINGTON (AP) — The House Ethics Committee confirmed Tuesday that it is investigating Republican Rep. John Duncan Jr., of Tennessee over unspecified allegations, after media reports last year that he had paid his son for campaign work.

Duncan Jr., who is serving his 16th term in the House and had previously announced he won't seek re-election, dismissed the complaint against him as "obviously very political" and done to deter him from running again.

The committee's announcement on Tuesday that it has decided to extend its review of Duncan is the first public acknowledgement of any investigation. The review was prompted by a referral in January from the nonpartisan Office of Congressional Ethics.

Duncan came under fire in early July after a Knoxville website reported that he paid his son $300,000 for campaign work in the years after the younger man pleaded guilty to misconduct in office. The congressman told the Knoxville News Sentinel that he paid John Duncan III to head his political operations and perform work ranging from putting up yard signs to fundraising.

The committee's Republican chairman and ranking Democratic member cautioned that the extension and public acknowledgement of the review does not itself indicate any violation has occurred.

Duncan said that he is confident the "Ethics Committee will resolve the matter in my favor."

Once the complaint was filed, a staffer with the Office of Congressional Ethics reviewed all of his campaign expenditures for the past decade, he said.

"Every expenditure I have ever made out of my campaign funds has been done to help me politically and to assist in my campaigns," Duncan said. "I have never taken one penny personally other than to pay for meals when I was eating with campaign workers, supporters, or constituents visiting Washington. This is perfectly legal."

Duncan said the Office of Congressional Ethics left it up to the Ethics Committee to decide whether a few of the larger expenditures were allowed to be paid for by campaign funds.

"I can and will assure the committee, if asked to do so, that they were all political and helped me in my campaigns," Duncan said.

Also known as "Jimmy," the congressman is a lawyer who served as a state trial judge before entering Congress. The 70-year-old Duncan was first elected to Congress in a 1988 special election to replace his father, John Duncan Sr., who had cancer and died in June of that year. He represents a district in the Knoxville area that is considered a safe Republican seat.

The Ethics Committee was required to publicly acknowledge the referral from the OCE within 45 days of receiving it.