Democratic House member Cori Bush is under federal investigation for allegedly using campaign money improperly on security services.
The Missouri lawmaker has been criticised for hiring her husband – and paying him – as part of her security detail.
Ms Bush has said she is cooperating with the investigation, and she did not misuse funds.
She has served as a member of the US House of Representatives since 2021.
In a statement she made on Tuesday, Ms Bush said that as a rank-and-file member of Congress, she is not entitled to personal protection by the House. Therefore, she said she has used campaign funds “as permissible” to pay for security services.
“I have not used any federal tax dollars for personal security services,” Ms Bush said. “Any reporting that I have used federal funds for personal security is simply false”.
Ms Bush added that she has become a recent target of right-wing organisations, whom she said “have lodged baseless complaints” against her.
She said some of the complaints have centred around her husband, Cortney Merrits, and his role as part of her campaign and security staff.
“I retained my husband as part of my security team to provide security services because he has had extensive experience in this area,” Ms Bush said.
“These frivolous complaints have resulted in a number of investigations, some of which are ongoing,” she added.
The Office of Congressional Ethics also investigated these allegations, she said, and concluded that her husband provided “bona fide” security work and did not appear to be overpaid.
Along with the justice department, Ms Bush said the House’s ethics committee and the Federal Election Commission are also reviewing her spending.
“I look forward to the same outcome from all pending investigations,” she said.
Throughout her time in Congress, Ms Bush, 47, has gained recognition as a member of The Squad – an informal group of progressive Democrats in the House of Representatives that includes Alexandria Ocasio-Cortez, Rashida Tlaib and Ilhan Omar.
In 2021, Ms Bush made headlines for campaigning overnight on the steps of the US Capitol to protest against the end of a Covid-related moratorium on rental evictions.
Since her election to office, Ms Bush has spoken out about being the target of death threats.