Special Counsel Robert Mueller has subpoenaed documents from the Trump Organization as part of his investigation into Russia's meddling in the 2016 U.S. election, The New York Times reported on Thursday, citing two people briefed on the development.
Some of the documents are related to Russia, the sources said.
The subpoena is the first known instance of Mueller ordering the production of documents directly from President Donald Trump's business during his nearly yearlong investigation into whether the Trump campaign colluded with Russia.
Trump has denounced the probe as a "WITCH HUNT!" and said in July that he would consider any investigation into his finances as crossing a red line.
"I think that's a violation," he said in a Times interview at the time. "Look, this is about Russia. So I think if he wants to go, my finances are extremely good, my company is an unbelievably successful company."
Mueller at the time had just asked Deutsche Bank, which has loaned the Trump Organization millions of dollars, to share information on accounts held by the Trump family.
A Trump Organization attorney said in a statement that the company continued to be "fully cooperative" with Mueller's investigation.
White House press secretary Sarah Huckabee Sanders declined to comment, and deferred questions to the Trump Organization.
The president reportedly attempted to fire Mueller in June, but reconsidered, several outlets reported in January.