WASHINGTON, D.C. – The House Committee on Foreign Affairs will hold a hearing Tuesday morning on Iran.

Members of the committee are working to find answers to questions that continue to swirl regarding the intelligence that led to the U.S. drone strike that killed Iranian Gen. Qassem Soleimani earlier this month.

The committee had invited Secretary of State Mike Pompeo to testify at the hearing to provide context on the use of military force and the overall strategy in the Middle East, but he rejected the invitation.

In response, Chairman Eliot Engel (D-N.Y.) said in a statement obtained by The Hill that he is “disappointed and frustrated” that Pompeo won’t appear before the committee.

The Hill reports that the hearing is scheduled to proceed with expert testimony from Council on Foreign Relations president Richard Haass, Brookings Institution nonresident senior Avril Haines, and former national security adviser Stephen Hadley.