Laura Cooper, the deputy assistant secretary of defense for Russia, Ukraine, and Eurasia, was set to testify at 10 a.m. ET this morning in one of the Sensitive Compartmented Information Facilities (SCIF) in the Capitol complex used by members of Congress to discuss classified information.

Cooper was expected to face questions about President Trump’s decision to withhold $391 million in security assistance to Ukraine. William Taylor, the top U.S. diplomat in Ukraine, testified on Tuesday that Trump withheld the funds while pressing Ukrainian President Volodymyr Zelensky to dig up dirt on his political rival, 2020 presidential contender and former Vice President Joe Biden.

The Republican lawmakers reportedly barged into the SCIF to demand Democrats hold open impeachment hearings. Republican members of the committees hearing Cooper’s testimony were already present in the room.

The Washington Post reported that Republican members committed a serious security breach by entering the SCIF with their cellphones, which some reportedly used while inside to send tweets. In audio uploaded to his Twitter account, Rep. Alex Mooney claimed to have placed a phone call inside the room.

The House sergeant-at-arms was eventually called to disperse the group and the hearing continued, but not before the SCIF had to be swept for rogue signals, according to several Capitol Hill reporters.

Neal Katyal, the former acting U.S. solicitor general, tweeted that the “stupidest” thing the GOP lawmakers could have done is bring electronic devices into the SCIF citing the risk of compromise by foreign spies. “You would your security clearance [and] may even face criminal prosecution,” he said of officials who violate the rules.

By noon, Bloomberg had reported that President Trump had advanced knowledge of the lawmakers’ plans to storm the secured area and had voiced support for interrupting Cooper’s testimony. CNN later confirmed the story citing a person familiar with the matter.

This is a developing story.