Following reports that White House aides have been using private email accounts to conduct official business, the leaders of the House Oversight Committee, Rep. Trey Gowdy (R-SC) and Rep. Elijah Cummings (D-MD), sent a letter to the White House on Monday asking that the administration identify any staffers using private email.

“With numerous public revelations of senior executive branch employees deliberately trying to circumvent [federal] laws by using personal, private, or alias e-mail addresses to conduct official government business, the Committee has aimed to use its oversight and investigative resources to prevent and deter misuse of private forms of written communication,” Gowdy and Cummings wrote in the letter to White House Counsel Don McGahn explaining their oversight request.

The congressmen cited a Sunday report in Politico that revealed Trump’s son-in-law and senior adviser Jared Kushner used private email to communicate with other members of the administration. Stephen Bannon and Reince Priebus, former administration aides, also used private email, according to Politico. Newsweek reported Monday that Ivanka Trump used her personal email in at least one instance to correspond with another administration official. At least six administration officials, including Gary Cohn and Stephen Miller, have used personal email accounts for White House business, the New York Times reported Monday.

The White House did not dispute reports that administration officials used personal email accounts for some official business on Monday. Press Secretary Sarah Huckabee Sanders said that personal email use in the Trump administration is “very limited” and noted that McGahn has instructed staff to only use their official email accounts.

Gowdy and Cummings asked McGahn to identify any White House staffers who have used a personal email account, an alias email, text messages, or encrypted message apps for official business to ensure that members of the administration are complying with laws governing record preservation.

The use of personal email accounts by members of Trump’s administration has drawn considerable attention given that Trump throughout the 2016 campaign painted Hillary Clinton as a criminal for using a private email server.

Read the letter from Gowdy and Cummings: