(CNN) US Ambassador to the European Union Gordon Sondland, a key witness within the State Department and to the President's action in the ongoing impeachment inquiry, intends to testify to the House under subpoena next Thursday, according to his lawyers.

Sondland's testimony will come amid a significant week in the Hill's efforts to hear from witnesses about the Trump administration's dealings with Ukraine, the core of the House impeachment inquiry.

Lawmakers have been eager to press Sondland about text messages he exchanged related to President Donald Trump's July phone call with Ukrainian President Volodymyr Zelensky and the freezing of foreign aid to Ukraine.

As of this morning, Sondland hasn't received guidance from the State Department on whether he should appear under subpoena, his lawyers said in a new statement on his behalf.

"Notwithstanding the State Department's current direction to not testify, Ambassador Sondland will honor the Committees' subpoena, and he looks forward to testifying on Thursday," his attorneys Robert Luskin and Kwame Manley wrote in a statement. "He has no agenda apart from answering the Committees' questions fully and truthfully."

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