U.S. Secretary of State Antony Blinken told lawmakers on Wednesday that the State Department has been putting together a review of the U.S. withdrawal from Afghanistan and will share findings with Congress by mid-April.

“We’ve now been spending time putting all of this together to make sure that we look at some of the common lessons learned,” Blinken said in testimony to a Senate Appropriations Committee subcommittee hearing.

“I am committed and determined to make that information available to Congress, and we will do that. We will do that by mid-April. So I can tell you today, you’ll have the after-action review. We will share the findings and find the appropriate mechanism to do that within the next three weeks.”

Members of Congress have been demanding information about the August 2021 withdrawal from Afghanistan after 20 years in what was the U.S.’s longest war. The Republican chairman of the House of Representatives Foreign Affairs Committee threatened this week to issue a subpoena if the State Department does not produce documents it has requested, Reuters reported.

John Kirby, the top spokesperson for the White House National Security Council, told reporters the main takeaways from the review would be released to the public and shared with the House committee.

Republicans, who took control of the House in January, say there has never been a full accounting of the chaotic operation, in which 13 U.S. service members were killed at Kabul’s airport.

Hundreds of U.S. citizens and many thousands of Afghans who had worked with American forces were left behind as they were seeking to flee from the Taliban, the Islamist militant group that resumed control of Afghanistan.