The inquiry aims to ensure that the Donald J. Trump Foundation complied with state laws, New York Attorney General Eric Schneiderman told CNN on Tuesday, without providing details.

It's not the first time that Schneiderman has come head-to-head with the presidential candidate. In 2013, he sued the Republican frontrunner over the now-defunct Trump University which he described as "straight up fraud." Schneiderman is also a Democrat and supporter of Trump's rival, Hillary Clinton.

In the televised interview, however, the attorney general said his actions were not politically motivated.

"My interest in this issue really is in my capacity as regulator of nonprofits in New York state," he said. "And we have been concerned that the Trump Foundation may have engaged in some impropriety from that point of view."

Trump fined over political donation

Also on Tuesday, a group of Democratic lawmakers called for a federal investigation into a $25,000 (23,200 euro) donation from the charity to a group linked with Florida Attorney General Pam Bondi in 2013. The payment came as Bondi's office was considering suing Trump for fraud over his training center in Florida. Bondi later decided against the suit.

"After receiving these funds, Mrs. Bondi declined to further investigate Mr. Trump's business interests. This fact pattern indicates that these payments may have influenced Mrs. Bondi's official decision not to participate in litigation against Mr. Trump" the Democrats on the House Judiciary Committee said in a letter.

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Trump later paid a $2,500 fine for breaking a law about charities and political contributions. His representatives claim the payment was a result of a series of clerical errors.

"A number of criminal statutes would appear to be implicated by this course of conduct," the Democrats said.

'Left-wing hit job'

The lawmakers cited reports by the Associated Press news agency that claim that Bondi personally solicited the donation. AP also claims that Trump's daughter Ivanka gave Bondi a personal check to $500 one week before the charity made the payment.

Trump's spokeswoman, Hope Hicks, confirmed that Trump and Bondi spoke before the donation, but said the two did not discuss any lawsuits. Neither side provided details on the conversation.

Florida's attorney general has said the timing of the donation was coincidental. She also called the AP report misleading.

Trump's charity foundation also faced other controversies, including reports from the Washington Post that Trump spent $20,000 of the funds to buy a six-foot (1.8-meter) high painting of himself. The newspaper also found four charities who claimed they never received money from the Donald J. Trump foundation, although the organization claims they donated to them.

According to the Post, Trump himself has not donated to his own charity since 2008.

Following Schneiderman's interview on Tuesday, the Trump campaign dismissed the probe as "nothing more than another left-wing hit job" and called the attorney general a "partisan hack."

dj/kms (Reuters, AFP, dpa, AP)