(CNN) The House Oversight Committee Wednesday invited White House senior policy adviser Stephen Miller to testify on the Trump administration's immigration policies on May 1.

Democratic Rep. Elijah Cummings, the chairman of the committee, sent a letter to Miller, the architect behind President Donald Trump's immigration policies, asking him to "appear voluntarily" before the committee. Miller is a prominent voice in the administration's immigration policymaking and has seen his influence rise in recent weeks, leading to a spate of prominent firings and resignations in the Department of Homeland Security.

"I am offering you an opportunity to make your case to the Committee and the American people about why you -- and presumably President Trump -- believe it is good policy for the Trump Administration to take the actions it has," Cummings wrote, "including intentionally separating immigrant children from their parents at the border to deter them from coming to the United States, transferring asylum seekers to sanctuary cities as a form of illegal retribution against your political adversaries, and firing top Administration officials who refuse orders to violate the law."

Cummings gave Miller until April 24 to inform the committee whether he will agree to testify.

CNN previously reported the President told aides in a recent Oval Office meeting that he was putting Miller in charge of all immigration and border issues, according to a person familiar with the meeting.

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