WASHINGTON (NEXSTAR) — President Biden officially declared the end of America’s longest war in an address to the nation Tuesday.

But now that all U.S. troops have returned from Afghanistan, the president faces mounting pressure from Republicans in Congress to answer questions about his handling of the evacuations and even to resign.

“It was designed to save American lives,” President Biden said of his Aug. 31 deadline. “I was not going to extend this forever war.”

However, the president acknowledged the final days cost 13 American service members their lives.

“We owe them and their families a debt of gratitude we can never repay,” he said. “But we should never, ever, ever forget.”

President Biden stressed their sacrifices helped evacuate more than 120,000 people from the Kabul airport, including nearly 6,000 Americans. He said about 100 Americans, mostly dual citizens, still remain in Afghanistan.

“The bottom line: 90 percent of Americans in Afghanistan who wanted to leave were able to leave,” he said.

But Republicans, like Rep. Rick Crawford, R-AR, question those numbers.

“Simple math would dictate that there are still several hundred if not thousands left behind,” Crawford said. “And that’s just unacceptable.”

Rep. Mark Green, R-TN, who served in Afghanistan, said leaving like this sends the wrong message to the rest of the world.

“You sure as heck can’t abandon Americans in a war zone… and expect our enemies to respect us,” Green said. “We have alienated our allies and empowered our enemies.”

That’s why many GOP lawmakers, like Sen. Tommy Tuberville, R-AL, are pressing the administration to answer questions over its handling of the withdrawal.

“Find out why in the world we did it the way we did it,” Tuberville said.

Others in the caucus, including Rep. Clay Higgins, R-LA, are supporting legislation that officially calls on President Biden to resign.

“We expect performance,” Higgins said. “And performance right now for President Biden calls for him to step down.”

A bipartisan group of lawmakers is taking a trip to the Middle East Wednesday to visit refugee camps.

Congressional committees are expected to hold public hearings on what went wrong in the final months of the withdrawal, including over why the administration did not begin evacuations earlier.