By The Associated Press

OKLAHOMA CITY (AP) — The National Rifle Association has sued its longtime advertising agency, accusing the company that has helped shape its Second Amendment advocacy of withholding crucial financial details in its billing documents.

The lawsuit filed Friday in Alexandria, Virginia, says Oklahoma City-based Ackerman McQueen is contractually bound to show backing paperwork on its bills to the NRA. But the NRA says the firm has only partly complied or "baldly ignored" requests for more information.

"Since July 2018, the NRA has provided more-than-reasonable notice of its desire to view key items," the lawsuit says. "However, the NRA's patience has run out."

The lawsuit says that in 2017 the NRA paid Ackerman McQueen and a subsidiary more than $40 million. The filing also says the ad agency refused to give information about a separate contract it had with NRA President and retired Lt. Col. Oliver North , the Marine at the center of the Iran-Contra affair three decades ago.

Ackerman McQueen said in a statement Monday that an NRA forensic auditing firm received every piece of information it requested during a three-week review.

"This flagrant misrepresentation, along with other false claims, serve as the foundation of malicious intent exemplified by this lawsuit," Ackerman McQueen's statement says.

Ackerman McQueen runs NRATV, which livestreams gun rights commentary and advocacy for the NRA. The company has worked with the NRA since the 1980s.

The lawsuit points out Ackerman McQueen helped craft some of the NRA's biggest messaging, including former organization president the late Charlton Heston's slogan about having to pry his guns "from my cold, dead hands."

In a statement, Ackerman McQueen also says NRA outside attorney William Brewer has a conflict of interest in the lawsuit because he is the son-in-law of and brother-in-law to two of the ad agency's directors.

Brewer's law first said in a statement that his familial relationships have "no bearing whatsoever on the NRA's litigation strategy."

The NRA is a powerful U.S. lobbying force and spent millions to help elect President Donald Trump, who will speak at the group's annual meeting later this month in Indianapolis. It will be Trump's third consecutive appearance at the meeting.