The chairs of the House Intelligence, Foreign Affairs and Oversight committees have subpoenaed U.S. Ambassador to the EU Gordon Sondland, who was blocked by the Trump administration from testifying in their Ukraine investigation on Tuesday, to turn over documents by Oct. 14 and appear at a deposition on Oct. 16.

The big picture: The chairs said in a statement that the State Department's decision to stop Sondland from testifying will be considered evidence of obstruction in their impeachment inquiry. They added that the State Department is withholding relevant messages from Sondland's personal device about the Trump administration's interactions with the Ukrainian government.

“These actions appear to be part of the White House’s effort to obstruct the impeachment inquiry and to cover up President Trump’s misconduct from Congress and the American people. Ambassador Sondland’s testimony and documents are vital, and that is precisely why the Administration is now blocking his testimony and withholding his documents."

— Chairmen Adam Schiff, Eliot Engel and Elijah Cummings

Background: According to the committees, "Sondland was at the center of the effort to orchestrate a Ukrainian statement confirming the initiation" of investigations into Joe Biden and alleged Ukrainian involvement in the 2016 election in exchange for a White House visit.

"The pressure on Ukraine took place as the White House also withheld hundreds of millions of dollars in vital military assistance to counter Russian aggression."

"Sondland and other State Department officials discussed whether military security assistance was being withheld from Ukraine as leverage to force the initiation of the political investigations."

Of note: A State Department official informed Sondland that he would not be permitted to testify at 12:30 a.m. on Tuesday morning, hours before he was set to appear on Capitol Hill, according to Sondland's attorney.

Read the subpoena:

Go deeper: Trump says he won’t let Sondland testify before House "kangaroo court"