(Bloomberg) -- Donald Trump’s presidential campaign may have illegally coordinated with the National Rifle Association in the final weeks of the 2016 presidential election, two watchdog groups said in a complaint filed Friday with the Federal Election Commission.

The NRA’s Institute for Legislative Action and its political action committee, the NRA Political Victory Fund, placed $25 million worth of television ads through the same ad-buying executives who also arranged spots for Trump’s campaign.

That ensured that “spending by both the NRA and the Trump campaign would be complementary and advance a unified, coordinated election strategy,” according to the complaint brought by the Campaign Legal Center, which favors greater regulation of money in politics, and the Giffords Law Center to Prevent Gun Violence, a gun safety group.

Federal election law bars campaigns and independent groups from coordinating their spending.

"There is reason to believe that the NRA-ILA and NRA-PVF made illegal, unreported and excessive in-kind contributions to Donald J. Trump for President, Inc. in the form of coordinated communications," according to the complaint. The groups are asking the Federal Election Commission to investigate the matter.

The complaint is the latest in a string of legal challenges to embroil the NRA this year. In April, the NRA said it received donations from about two dozen individuals with Russian addresses. U.S. authorities are reportedly investigating if the gun-rights group funneled Russian money into the 2016 presidential election. The NRA didn’t respond to a request for comment.

To contact the reporters on this story: Bill Allison in Washington at ballison14@bloomberg.net;Polly Mosendz in New York at pmosendz@bloomberg.net

To contact the editors responsible for this story: Jeffrey D Grocott at jgrocott2@bloomberg.net, ;Sara Forden at sforden@bloomberg.net, David S. Joachim

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