WASHINGTON — Representatives Seth Moulton, Democrat of Massachusetts, and Peter Meijer, Republican of Michigan, stunned Washington when they secretly flew to Kabul on Tuesday on an unauthorized mission to witness the evacuation of Americans and Afghans.

The lawmakers — Iraq war veterans who have emerged as two of the toughest critics of the Biden administration’s withdrawal — took a commercial flight to the United Arab Emirates, where they boarded a military plane to Afghanistan’s capital. They spoke with State Department officials and U.S. commanders and troops on the ground, and saw throngs of Afghans at the gates outside Hamid Karzai International Airport.

The unauthorized trip infuriated administration officials who were already annoyed by the lawmakers’ outspoken criticism and drew bipartisan rebukes from Speaker Nancy Pelosi of California and Representative Kevin McCarthy of California, the Republican leader. John F. Kirby, the Pentagon spokesman, said the trip “certainly took time away from what we had been planning to do that day.”