Investigators for Russia special counsel Robert Mueller last month subpoenaed Trump campaign officials for Moscow-related documents from more than a dozen top officials, The Wall Street Journal reported Thursday.
The report was based on "a person familiar with the matter."
The subpoena was Mueller's first official directive for information from President Donald Trump's campaign, according to the Journal, though officials have been complying with requests for documents beforehand.
However, Mueller's subpoena did not compel any officials to testify before a grand jury, the report noted.
The campaign is complying with the subpoena by providing the information on an "ongoing" basis.
A Mueller spokesman declined to comment.
The special counsel is investigating Russia's meddling in last November's presidential election.
The Kremlin has denied any involvement — and President Trump has slammed the investigation as a "witch hunt."
Previous Mueller subpoenas have been served to former Trump campaign chairman Paul Manafort and former National Security Adviser Mike Flynn.
Manafort was indicted this month on charges of tax evasion and money laundering.
He has pleaded not guilty and Keving Downing, his attorney, has attacked the charges as "ridiculous."
In addition, Mueller's team is expected to soon interview White House Communications Director Hope Hicks, the Journal reports.
Previous Trump officials who have been queried include former Chief of Staff Reince Priebus and Hicks' predecessor, Sean Spicer.