President Trump is spending cash donated to his reelection campaign and the Republican National Committee to pay for his lawyers in the criminal probe of Russian interference in the election, a new report said Tuesday.

The Federal Election Commission allows the use of private campaign funds to pay legal bills arising from being a candidate or elected official.

But while previous presidential campaigns have used these funds to pay for routine legal matters such as ballot access disputes and compliance requirements, Trump would be the first president in the modern campaign finance era to use such funds to cover the costs of defending himself in a criminal probe, said election law experts.

A source familiar with the matter told Reuters, which first reported the story, the first payments, the amount of which was not available, had already been made and would be disclosed in public filings.

The source did not explain how much came from the campaign and the how much came from the RNC.

The committee is expected to make its August spending public on Wednesday, and the Trump campaign is due for another disclosure on Oct. 15.

John Dowd, Trump’s lead lawyer, declined to say how the president’s legal bills were being paid.

“That’s none of your business,” he snapped.

A spokesperson for the RNC declined to comment, but said the committee has already paid unspecified, non-Russia related litigation expenses for the campaign.

The committee has an existing legal defense fund which has been used mainly for Election Day recounts and other routine legal matters for candidates, the spokesperson said.

Special counsel Robert Mueller is looking at possible collusion between the Trump campaign and Russia in last year’s election, and whether Trump may have obstructed justice by firing FBI Director James Comey, among other actions. Trump denies any collusion or obstruction.

Reuters could not determine how large a legal bill Trump has incurred to date from his lawyers on the Mueller probe.

Trump hired his longtime New York lawyer Marc Kasowitz to head his defense team in May, but Kasowitz stepped down in July, with Dowd taking over the lead role.

Trump is also being represented by constitutional lawyer Jay Sekulow. Special White House counsel Ty Cobb, who is a salaried staff member, is also working on the matter.

The Trump campaign has paid law firm Jones Day almost $4 million, according to campaign filings, mostly for routine campaign legal expenses like ballot access disputes, vendor contracts, human resources and compliance with state and federal laws.

The reason Trump is able to tap into his campaign funds for legal expenses is because for the past decade, presidential candidates have abandoned public financing for their campaigns.

Instead, they have built networks that collect millions of dollars from private donors, a move that comes with less restrictions on how the money is spent.

According to its most recent filing to the Federal Election Commission, Donald J. Trump for President Inc had almost $12 million on hand by the end of June, an increase of over $4 million since January.

Hillary Clinton, who ran a privately funded campaign, paid millions to campaign lawyers at Perkins Coie to handle routine legal matters, according to campaign filings.

Her campaign made no payments to the Washington law firm Williams & Connolly, which represented her in the probes of her use of a private email server when she was US Secretary of State.

With Reuters