The State Department’s inspector general has requested a bipartisan staff briefing with relevant congressional committees tomorrow related to documents on Ukraine, according to sources briefed on the matter.

The email that went to staff suggested it was “urgent,” sources said.

A congressional aide described the inspector general's request as “highly unusual and cryptically worded.”

The source also said that the inspector general stated the office had obtained documents from the acting legal adviser at the State Department.

Congressional sources tell CNN that the inspector general is expected to brief committee staff from House Foreign Affairs, Senate Foreign Relations, House and Senate Appropriations, House Oversight, Senate Homeland Security and Governmental Affairs and both House and Senate intelligence committees. The briefing will be held in a secure meeting room in the Capitol.

The offer for documents came roughly an hour after Secretary of State Mike Pompeo’s strongly worded letter pushing back against the Democrats scheduled depositions of state officials and subpoena for documents, sources said.

ABC News first reported this story.