President Donald Trump on Monday accused the New York attorney general and Gov. Andrew Cuomo of illegally investigating the National Rifle Association, and implored the group, which has recently been entangled in a leadership crisis, to "get back to greatness."

"The NRA is under siege by Cuomo and the New York State A.G., who are illegally using the State's legal apparatus to take down and destroy this very important organization, & others," Trump tweeted Monday . "It must get its act together quickly, stop the internal fighting, & get back to GREATNESS - FAST!"

New York Attorney General Letitia James' office on Saturday said it had launched an investigation into the pro-gun organization and issued subpoenas to the group, according to The New York Times. James' office last week instructed the NRA and its affiliated entities to preserve relevant financial records, according to reports.

James has previously said she would investigate the organization's nonprofit tax-exempt status. She has jurisdiction over the group because it was chartered in New York, according to the Times.

The investigation coincides with public and bitter infighting among leaders of the group. Oliver North said Saturday he would not serve a second term as NRA president and did not show up to the group's annual convention over the weekend.

North, a retired Marine officer and key Iran-Contra figure, had earlier in the week tried to oust longtime chief executive Wayne LaPierre. LaPierre on Thursday sent a letter to the organization's board accusing North of threatening to release harmful information about him and other leaders if he did not resign.

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The letter from LaPierre alleged that North is threatening to release information that would include "a devastating account of our financial status, sexual harassment charges against a staff member, accusations of wardrobe expenses and excessive staff travel expenses."

North had previously gone to the organization's board with allegations about LaPierre, including saying that the leader charged more than $200,000 in wardrobe expenses to an NRA vendor, according to The Wall Street Journal.

LaPierre said he was "disgusted" by North's actions which LaPierre labeled extortion. The dispute is connected to a lawsuit filed by the NRA against its ad firm, Ackerman McQueen, which North has a relationship with.

According to The Wall Street Journal, the probe by the New York attorney general's office will investigate "related-party transactions between the NRA and its board members; unauthorized political activity; and potentially false or misleading disclosures in regulatory filings."