The legislative assistant to the commandant of the Marine Corps has been suspended from his post amid allegations of a hostile work environment, the service announced Wednesday.

Brig. Gen. Norman L. Cooling was removed after Defense Secretary Jim Mattis received a request from Congress to investigate his behavior, according to a news release. The Senate Armed Services Committee asked Mattis directly to review the command climate Cooling had created during his tenure at the post, officials said.

The office of the secretary of defense is now investigating the allegations.

A Marine Corps spokesman, Maj. Brian Block, said the length of the investigation would be determined by OSD; there's no defined time limit to Cooling's suspension.

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Marine Corps Commandant Gen. Robert Neller, who personally removed Cooling from his post, said in a statement that the service planned to give full cooperation to the Department of Defense as officials complete their review.

"We are committed to being an organization in which every Marine has the opportunity to serve at their full potential, unimpeded by discrimination, bias, or hostile working conditions," he said.

Cooling, an infantry officer, graduated from the U.S. Naval Academy in 1982, according to his biography. He's a veteran of combat in Iraq and Afghanistan and previously served as deputy director, J-3 Plans and Operations for U.S. European Command in Stuttgart, Germany. He became legislative assistant to the commandant in July 2017.

The news of Cooling's suspension comes just ahead of the one-year anniversary of an explosive story that revealed the existence of Marines United, a private Facebook group used by some troops and veterans to circulate nude photographs of female service members without their consent.

In the wake of that scandal, which prompted multiple congressional hearings, the Marine Corps launched an aggressive multi-pronged effort to create greater accountability for bad behavior on social media and promote respect in the ranks.

Last August, Assistant Commandant Gen. Glenn Walters revealed that two of the five Marine Corps unit commanders that had been relieved that year to date were removed from their posts in connection with a negative command climate including the issue of Marines' improper behavior toward women.

""Their [unit's] behavior toward women was a component of that decision. And that's as far as I'd like to go," Walters said at the time. " ...They didn't do what we want commanders to do and exhibited the wrong behavior as a commander."

Walters plans to hold a round table for reporters Friday to discuss additional steps taken in the last year to address gender bias and social media misconduct.

-- Hope Hodge Seck can be reached at hope.seck@military.com. Follow her on Twitter at @HopeSeck.