Former national security adviser Michael Flynn. Thomson Reuters House Intelligence Committee investigators looking into potential ties between the Trump campaign and Russia have obtained documents from former national security adviser Michael Flynn, CNN reported Thursday.

"We're going through the documents we've received from various witnesses, including Gen. Flynn, to determine if they meet the requirements of the documents we've asked for," said ranking committee member Rep. Adam Schiff.

The batch of documents arrived after subpoenas were issued to Flynn and to businesses with which he is associated, CNN's report said. Subpoenas were also sent to Trump's longtime personal attorney, Michael Cohen.

According to CNN, Flynn also supplied 600 pages of documents to the Senate Intelligence Committee after receiving its subpoenas and reaching an agreement with that committee's investigators.

Following the Senate intelligence committee's denial of Flynn's request for immunity from prosecution in exchange for his testimony, Flynn pleaded the Fifth Amendment to reject the subpoena. Lawmakers later subpoenaed businesses associated with Flynn in response.

Investigators conducting the Trump-Russia inquiry have focused more closely on Flynn in recent months, due in part to his previously undisclosed payments from a Russian state-run media outlet in 2015 and his work on behalf of foreign entities.