A key House committee is demanding a briefing from Secretary of State Mike Pompeo on Jared Kushner’s trip to Saudi Arabia last month that included a senior State Department official but otherwise left American diplomats in the dark.  

In a letter sent Thursday, House Foreign Affairs Chairman Eliot Engel (D-NY) expressed concern that embassy staff were reportedly sidelined from participating in the meetings on that trip, including those with the Royal Court and Crown Prince Mohammed Bin Salman.

“U.S. government resources are expended to support embassies in countries around the world to aid in the planning and execution of U.S. foreign policy, and no official visit to the Middle East by a senior White House aide would presumably bear meaningfully on the conduct of U.S. foreign policy in that region,” he wrote, adding that he wanted a briefing no later than April 5.

The briefing, he said, should also provide details of any foreign trips or overseas meetings between senior White House officials and foreign leaders in the Middle East.

The congressman is seeking detailed documents from the February trip, including aircraft manifests, clearance records for each person who traveled, invoices and expense reports, and records relating to the State Department’s participation in the trip.

The letter goes on to mention Brian Hook, the department’s special representative for Iran, who traveled with Kushner. Hook is one of several current and former State Department officials under investigation by the Office of the Inspector General for alleged politically motivated personnel decisions.

Engel is also seeking “all emails sent or received” by Hook relating to the trip and records, including handwritten notes, that correspond to the meetings Hook attended.

Kushner, Hook, and Trump’s Middle East envoy Jason Greenblatt flew to Riyadh as a part of a larger trip to the region where the president’s son-in-law would discuss the details of his Middle East peace plan. The team met with Crown Prince Salman and his father King Salman in Saudi Arabia.

“Building on previous conversations, they discussed increasing cooperation between the United States and Saudi Arabia, and the Trump Administration’s efforts to facilitate peace between the Israelis and Palestinians,” a White House statement said. “Additionally, they discussed ways to improve the condition of the entire region through economic investment.”

But lawmakers told The Daily Beast they were concerned about the lack of oversight from officials inside the Saudi embassy in Riyadh, especially in the wake of the killing of Jamal Khashoggi and the increased attention on a possible nuclear deal between the two countries.

The Daily Beast reported on Wednesday that the Department of Energy has approved six authorizations for U.S. companies seeking to conduct nuclear-related work in Saudi Arabia. The authorizations—known as Part 810s, referring to a clause in federal regulations —allow U.S. companies to divulge specific details about plans for working in Saudi Arabia and certain information about the nuclear technology.

It’s still unclear which companies have received those authorizations. The DOE has not responded to a Daily Beast Freedom of Information Act request.

Editor’s Note: This story has been updated to show that Ranking Member Rep. Michael McCaul (R-TX) was not a signee of the letter, as had been earlier reported.