Rep. Chris Van Hollen (D-Md.) (Marvin Joseph/The Washington Post)

A powerful Democratic women’s group says Rep. Chris Van Hollen (D-Md.) has been targeting its donors to peel away support from his primary rival, Rep. Donna F. Edwards, for Maryland’s open Senate seat.

In a complaint filed Monday to the Federal Election Commission, Emily’s List said that Van Hollen illegally used the group’s financial disclosures to send a fundraising solicitation to its donors. While FEC reports are public, it is illegal to use those disclosures to find names and addresses for solicitations.

“We are taking action to protect you from actors willing to abuse the system,” Emily’s List President Stephanie Schriock said in a letter to donors who have supported Edwards.

Supporters in at least 11 states got a letter and solicitation from the Van Hollen campaign. The campaign letter, by former ­NARAL Pro-Choice America board Chairman Rosalyn Levy Jonas, refers to an email in which Emily’s List identified Van Hollen incorrectly as a Republican.

“Sadly, Emily’s List, which I have always supported in the past, has become a party to . . . deception,” Jonas said.

Emily’s List says that the email was an honest mistake sent only to a test audience of 5,000 people and that it immediately offered to send a correction.

In her letter, Jonas touts Van Hollen’s credentials on women’s issues, saying he helped elect female candidates when he was chairman of the Democratic Congressional Campaign Committee, is a close ally of House Minority Leader Nancy Pelosi (D-Calif.), and has the backing of a co-chair of the House Pro-Choice Caucus, Rep. Louise M. Slaughter (D-N.Y.).

“Given the explicit organizational affiliation by our former board chair in a letter on behalf of Chris Van Hollen, we want to be clear that we had no knowledge of the letter prior to its dissemination,” NARAL President Ilyse Hogue said in a statement. “We feel lucky to have two solidly pro-choice legislators in this critically important race.”

Van Hollen campaign manager Sheila O’Connell, who is a former Emily’s List political director, called the complaint “a politically motivated and frivolous attack that we are confident will be dismissed.”

Van Hollen’s campaign would not directly deny relying on Emily’s List disclosures but noted that campaigns often rent or swap lists of potential donors.

FEC complaints are often filed during campaigns and not resolved until long after those campaigns end because of how slowly the agency operates.

Regardless of how the agency rules, the complaint is a sign of the tension between Van Hollen’s and Edwards’s allies.

Van Hollen has repeatedly argued that effectiveness, not identity, should guide voters in this race and that his record on women’s rights is the stronger one.

But Emily’s List backs only female Democratic candidates who support abortion rights, and the group has gone after Van Hollen aggressively. With the primary more than four months away, the group has put $1 million into ads supporting Edwards. Van Hollen, in response, sent a fundraising email lamenting “dark money” and “misleading ads” — but never mentioned the group by name.

Van Hollen is far better funded than Edwards and has pressured her to give up any super PAC support. Edwards has defended her reliance on outside money, saying that as the underdog in the race, she needs help to compete. Polling has varied; the most recent survey from the Baltimore Sun gives Van Hollen a sizable lead.

The two candidates are vying for the Democratic nomination to replace Sen. Barbara A. Mikulski (D), the longest-serving woman in Congress. The primary is April 26.