Democratic lawmakers are urging Federal Reserve Chairman Kevin Warsh to disclose any calls or conversations he has had with President Donald Trump since taking over the central bank in May. The lawmakers request disclosure of any communications that occurred after Warsh began his role, citing the need for transparency around interactions with the White House.

The request is sent in the form of a letter, according to one outlet. Bloomberg reports the lawmakers’ push is prompted by reporting that Trump has periodically spoken with Warsh by phone since he became chair. Both sources focus on the same core issue: whether Warsh’s communications with the president should be publicly documented. Neither source provides additional details on the substance of the calls, the number of contacts, or any response from the Fed.