Washington (CNN) The chairman of the House Oversight Committee on Monday said the panel will vote to hold White House counselor Kellyanne Conway in contempt of Congress later this month unless she agrees to appear to testify in a hearing.

Despite a subpoena to testify last month, Conway did not appear at the committee's hearing Monday. Chairman Elijah Cummings, a Maryland Democrat, said the committee will hold a contempt vote on July 25, but implored Conway to testify before then to "help us avoid that situation."

A letter sent to Cummings from White House counsel Pat Cipollone ahead of the hearing Monday said Conway would not appear at the direction of President Donald Trump.

"The President has directed Ms. Conway not to appear at the Committee's scheduled hearing on Monday, July 15, 2019," the letter said. "The long-standing principle of immunity for senior advisers to the President is firmly rooted in the Constitution's separation of powers and protects the core functions of the Presidency."

The White House also released a statement calling the House Oversight Committee's subpoena a "purely political campaign."

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