Paul Singer

USA TODAY

Corrections and clarifications: This story has been updated to clarify that Rep. Huffman's email included a link to sign up for information from his campaign, not a direct fundraising appeal.

WASHINGTON — An independent watchdog group is filing an ethics complaint against several House Democrats for violating House rules last week during lawmakers' 25-hour sit-in to demand votes on gun control.

The Foundation for Accountability and Civic Trust, a conservative-leaning ethics watchdog group, filed a complaint with the House Office of Congressional Ethics on Monday arguing that lawmakers violated ethics rules by fundraising around specific legislation and by using House resources for political purposes.

The House ethics manual states: "The House buildings, and House rooms and offices – including district offices – are supported with official funds and hence are considered official resources. Accordingly, as a general rule, they may not be used for the conduct of campaign or political activities. Thus, for example, a Member may not film a campaign commercial or have campaign photos taken in a congressional office."

Democrats end House sit-in after 25 hours of demanding votes on gun control

But at least two Democrats, Jared Huffman of California and Ben Ray Lujan of New Mexico, sent campaign emails during the sit-in featuring images of them engaged in the protest on the House floor. Lujan's appeal specifically requested a donation; Huffman provided a link to a signup for his campaign website.

House rules also prohibit fundraising inside a federal building, but Rep. Jan Schkowsky, D-Ill., sent a fundraising email Wednesday night saying "I'm asking you while sitting here on the House floor" for a donation. Schakowsky was not named in the FACT complaint.

FACT argues that beyond the use of images from inside the House chamber, the solicitations violate the ethics manual's prohibition on connecting a fundraising solicitation to a specific legislative act. The group cites fundraising emails sent by the House Democrats' campaign operation that referenced Minority Leader Nancy Pelosi and sit-in leader Rep. John Lewis demanding a vote on gun control legislation.

"It it boils down to the tying of taking a vote on a piece of legislation to the fundraising," said FACT Executive Director Matthew Whitaker. "If you are going to have these high-minded rules that go to the heart of good-faith representation ... why not just repeal the rules if you have no intention of following them," Whitaker said.

Pelosi spokesman Drew Hammill dismissed the complaint as "ridiculous and without merit."

Rob Walker, a former chief counsel of the House Ethics Committee, said using images from the floor for fundraising appears to be a clear violation of House rules, but he added that the House could decide not to pursue the violators. The gun debate in Congress is an area of "intense partisan feelings," which is "never a good context for a matter to go to the Ethics Committee."

During the sit-in, several lawmakers broadcast the sit-in using social media channels including Facebook Live video and the Twitter app Periscope, which is also a violation of House rules that prohibit video on the House floor.

How C-SPAN is skirting the House TV blackout on Democrats' sit-in

Rep. Beto O'Rourke, D-Texas, whose video feed was rebroadcast by C-SPAN, told USA TODAY last week, "I was asked by the Sergeant at Arms to turn it off because it was against the rules and I said 'so is sitting on the floor of the House.' "

O'Rourke said breaking House rules is "an option of last resort when there is not another way to be able to achieve your goal ... in the tradition of other acts of civil disobedience." There has been no suggestion O'Rourke was improperly fundraising.

Speaker Paul Ryan, R -Wis., said last week that the House would not tolerate continued disruptions. "We are not going to allow stunts like this to stop us from carrying out the people's business," but he was not specific about how the House respond if lawmakers tried to resume the protest after the July Fourth recess.

Ryan Spokeswoman AshLee Strong said Monday, "We are discussing next steps this week while the House is in the district work period.”