WASHINGTON (Reuters) - U.S. House Democrats said they plan to issue a subpoena on Tuesday for the U.S. ambassador to the European Union after the Trump administration blocked his planned appearance before lawmakers as part of Congress’ impeachment probe.

“We consider this interference to be obstruction of the impeachment inquiry,” the heads of the House intelligence, foreign affairs and oversight panels said after the State Department blocked the diplomat, Gordon Sondland, from appearing before Congress earlier on Tuesday.