WASHINGTON (AP) — A Democratic senator charges in a new report that the National Rifle Association acted as a "foreign asset" for Russia in the run-up to the 2016 election, and that NRA insiders provided access to the American political system to advance personal business interests.

The report by Oregon Sen. Ron Wyden, the top Democrat on the Senate Finance Committee, also says NRA leaders may have violated tax laws that prohibit use of organization resources for personal benefit.

The report, based on an 18-month investigation, found that NRA leaders "engaged in a years-long effort to facilitate the U.S.-based activities" of Russian nationals Maria Butina and Alexander Torshin.

Butina is serving 18 months in prison after admitting she covertly gathered intelligence on the NRA at the direction of Torshin, a former Russian lawmaker.