FIRST ON FOX: A key House committee is widening its probe into the major Democratic fundraising platform ActBlue.

Rep. Bryan Steil, R-Wis., who chairs the Committee on House Administration, is investigating ActBlue over accusations it’s skirting campaign donation laws that allow for rampant fraud on the site.

In a letter sent to top officials on the Federal Election Commission (FEC) on Monday, Steil urged them to "immediately initiate an emergency rulemaking to require political campaigns to verify the card verification value (‘CVV’) of donors who contribute online using a credit or debit card, and to prohibit political campaigns from accepting online contributions from a gift card or other prepaid credit cards."

Republicans on the committee and other GOP officials have for months accused ActBlue of lax donor verification standards.

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Bryan Steil, Kamala Harris

House Committee on Administration Chair Bryan Steil is probing the Democratic fundraising giant that's helped Vice President Kamala Harris bring in millions. (Getty Images)

"Following widespread allegations of fraudulent donations being reported to the FEC by ActBlue, one of the largest fundraising platforms in the country, this emergency rulemaking is necessary to reassure the American people that ActBlue is taking the necessary steps to protect its donors," Steil wrote.

According to his committee, whistleblowers who approached the panel in recent weeks have accused ActBlue of deliberately not using CVV numbers for donations to reduce the bar for verification. 

Whistleblowers have also reported the receipt of a significant number of donations from retirees living on a fixed income, and hundreds of donations of $2.50 from the same individual, according to the committee.

The site has been used to raise millions of dollars for Vice President Kamala Harris as she seeks to take on former President Trump in November.

As of Monday morning, however, a CVV number was required on the page accepting credit card donations for the vice president.

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Wallet with multiple debit/credit cards

Steil accused ActBlue of accepting donations via prepaid debit card and gift cards, which he said could be used to launder foreign donations. (CyberGuy.com)

A CVV number was also required for credit card donations to several Democratic House candidates’ ActBlue pages checked by Fox News Digital, though donations were also accepted via Paypal, Venmo and Google Pay, which did not require the user to input such information.

As of spring last year, however, the FEC did not impose specific rules requiring CVV numbers for online political donations.

Steil’s letter also argued that the site’s acceptance of prepaid credit cards and gift cards fueled a "very real possibility that straw donors are making campaign donations with funds provided by another person or an unlawful donor including a foreign national. These issues present a serious loophole to the transparency and integrity of the campaign donation process, and an emergency rulemaking is required to rectify these issues."

The committee said whistleblowers have also claimed prepaid gift cards and credit cards are being used to launder campaign contributions that would otherwise violate campaign finance laws.

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It comes after similar investigations were launched by the GOP attorneys general of Virginia, Wyoming and Missouri last week.

ActBlue told Newsweek in response to those probes, "This investigation is nothing more than a partisan political attack and scare tactic to undermine the power of Democratic and progressive small-dollar donors. We welcome the opportunity to respond to these frivolous claims."

The FEC declined to comment when reached by Fox News Digital.

ActBlue and the Harris campaign did not respond to requests for comment.