The State Department blocked a top U.S. diplomat from giving a scheduled deposition Tuesday before a House panel conducting the impeachment inquiry into President Donald Trump.

Gordon Sondland, the U.S. ambassador to the European Union, is a witness to Trump’s efforts to persuade Ukraine to investigate former Vice President Joe Biden, a front-runner in the 2020 Democratic presidential primary race.

Sondland is “profoundly disappointed” that he won’t be able to testify Tuesday and hopes the issues raised by the State Department will be resolved promptly, his attorney Robert Luskin said.

“Ambassador Sondland believes strongly that he acted at all times in the best interest of the United States, and he stands ready to answer the Committee’s questions fully and truthfully,” Luskin said in a statement.

The Trump administration’s directive came just hours before Sondland was scheduled to meet for a closed-door session with staff of three Democratic-led House committees.

Trump tweeted that he’d “love” to have Sondland, a former hotel executive who donated $1 million to Trump’s inaugural committee in 2017, testify Tuesday if not for “a totally compromised kangaroo court.”

House Intelligence Committee Chair Adam Schiff (D-Calif.) said during a press conference on Capitol Hill that efforts by Trump and Secretary of State Mike Pompeo to block testimony and withhold documents are “evidence of obstruction.”

Schiff added that Sondland had “deeply relevant” text messages on a personal device that he provided to the State Department, which then refused to hand them over to Congress.

Schiff, along with the chairs of two other House committees leading the impeachment inquiry, later announced they will subpoena Sondland for his testimony and documents.

“Ambassador Sondland’s testimony and documents are vital, and that is precisely why the Administration is now blocking his testimony and withholding his documents,” the committee chairs said in a statement.