The National Rifle Association acknowledged in a letter to Congress Tuesday that it had accepted 23 contributions since 2015 from Russians or Americans living in Russia.

The letter , which was sent to Sen. Ron Wyden, D-Ore., and unveiled Wednesday, revealed the sum total of those contributions was just over $2,500, comprised mostly of “routine payments” like membership dues or magazine subscriptions. The letter was first reported by NPR.

Following reports that the FBI is investigating the possibility that Russians may have tried to use the NRA to attack the 2016 election, Wyden has been questioning the NRA about connections it might have with Russia.

Russian state bank official Alexander Torshin has been a lifetime member of the NRA since 2012, but the NRA says he has never made any contributions past his membership dues.

An aide to Wyden, who asked not to be named, told NPR the NRA’s revision of previous statements is causing the senator to consider how he might continue questioning the organization.

"After three letters, the NRA continually, and specifically avoided detailing what measures it takes to vet donations, including from shell companies, a known means for Russians to funnel money into the United States," the aide said.

"Sen. Wyden will be referring his correspondence with the NRA to the Federal Elections Commission to contribute to their inquiry ... As ranking member of the Finance Committee, he is considering additional oversight actions in light of this response."