Special counsel Robert Mueller subpoenaed President Donald Trump's businesses "in recent weeks" for documents, some of which relate to Russia, The New York Times reported, citing two people briefed on the matter.

The newspaper says it marks the first time Mueller, who is probing Russian involvement in the 2016 election, has asked for information directly related to the Trump Organization. The action comes as the former FBI director appears to be looking into the role foreign money could have played in the president's political activities, the newspaper reported.

It is unclear exactly what information Mueller requested. Trump and his lawyers have sought a swift end to the investigation, but the subpoena indicates it could continue for at least a few more months, the Times said.

Trump has previously said he believes the special counsel investigating his finances would cross a red line. The Trump Organization has denied holding real estate in Moscow. His company considered developing a Trump Tower in Moscow in late 2015 and early 2016 before abandoning the plan, The Washington Post reported.

Earlier this month, former Trump aide Sam Nunberg said investigators wanted information about the Trump Tower plans.

Trump has repeatedly denied any wrongdoing or coordination with Russia during the 2016 election.

The special counsel's office and a lawyer for Trump declined to comment. The White House referred questions to the Trump Organization, which did not immediately respond to a request to comment.