Malley, a veteran diplomat who has served in multiple Democratic administrations, had been working to restore the 2015 Iran nuclear deal. As POLITICO has reported, he was put on partial leave this spring amid an investigation into whether he should have access to classified information. State turned that into a full-time, unpaid leave in late June when news of the probe, which involves the FBI and Diplomatic Security, became public.

Republican lawmakers have criticized the administration both for allowing Malley to continue to work in the department after his security clearance was suspended over the investigation and for keeping them in the dark about the probe for several weeks.

In mid-July, McCaul threatened to subpoena State Department officials if he didn’t get a briefing on the circumstances surrounding Malley’s suspension by Wednesday.

McCaul hasn’t said whether he will drop the threat and may not decide until after the briefing.

The State Department hasn’t publicly acknowledged what prompted Malley’s break from his job and Malley has denied wrongdoing.

Without offering evidence, McCaul has questioned whether Malley may have “transferred intelligence and secrets to our foreign nation adversary,” saying such an action, “would be treason in my view.”

In a statement, the State Department said it is in communication with the committee about its requests for additional information, adding “we anticipate providing briefings for the committee.”

Malley, who was named envoy in January 2021, has many detractors, including among groups that want the United States to take a harder line on Iran’s Islamist government.

But both Secretary of State Antony Blinken and national security adviser Jake Sullivan have expressed support for Malley, while declining to discuss the investigation directly.

Malley has said previously that he was told his clearance was under review but not given further information. Asked for comment for this story, Malley said: “I know that I have done nothing to jeopardize U.S. national security interests and remain fully confident that this will be resolved positively.”