Former U.S. Vice President Mike Pence has been subpoenaed by the special counsel investigating former President Donald Trump’s efforts to cling to his office after he lost his bid for reelection, a person familiar with the matter said Thursday.

The move by the Justice Department sets up a likely clash over executive privilege, which Trump has previously used to try to slow, delay and block testimony from former administration officials in various investigations into his conduct.

The existence of the subpoena was reported earlier by ABC News.