WASHINGTON — US President Joe Biden on Wednesday suggested for the first time that he's willing to keep US forces in Afghanistan until all American citizens who want to leave are out of the country, but stopped short of making the same commitment to the United States' Afghan partners.

In an interview with ABC News, Biden said Americans should expect for all US citizens in Afghanistan to be evacuated by Aug. 31, the deadline the administration has set for ending the nation's longest war.

Asked if Americans should understand that US forces may be in Afghanistan past Aug. 31, the president responded "No, Americans should understand that we're going to try and get it done before Aug. 31." But, he added, "if there's American citizens left, we're going to stay until we get them all out."

The potential commitment to extending American forces' stay in Afghanistan for evacuations past the end of the month does not necessarily apply to extending US-led evacuations for Afghans who worked with the US during the war.

Biden said the US estimates between 50,000-65,000 Afghan partners and their families are trying to get out of the country. In order to get them out of the country before the Aug. 31 deadline, the president said, evacuations will have to ramp up.

Asked if he would keep US troops there if they weren't all out, Biden said, "The commitment holds to get everyone out that, in fact, we can get out and everyone that should come out. ... That's the path we're on. And I think we'll get there."

The president also defiantly defended his administration's execution of the withdrawal of US troops from Afghanistan, saying that he doesn't think the crisis represents a failure and there was no way to better handle the drawdown.

Biden was asked if it was a failure of intelligence, planning, execution or judgment that led to the situation in Afghanistan. "I don't think it was a failure," the President responded.

He added, "When you had the government of Afghanistan, the leader of that government getting into a plane and taking off and going to another country. When you saw the significant collapse of the Afghan troops we had trained, that was -- you know I'm not -- that's what happened. That's simply what happened."

Asked if he thought the withdrawal could have been handled better, Biden said: "No."

Biden defended his decisions, saying problems were inevitable in ending the 20-year US involvement there. “The idea that somehow, there’s a way to have gotten out without chaos ensuing, I don’t know how that happens,” he said.

He also said the Taliban is cooperating for now in helping get Americans out of the country but “we’re having some more difficulty” in evacuating US-aligned Afghan citizens.

In another development, the Pentagon said the US military does not currently have the ability to reach people beyond the Kabul airport.

“We’re going to do everything we can to continue to try and deconflict and create passageways for them to get to the airfield. I don’t have the capability to go out and extend operations currently into Kabul,” US Defense Secretary Lloyd Austin told reporters at the Pentagon.

A top US diplomat separately said on Wednesday the United States expects the Taliban to allow Afghans who wish to leave Afghanistan to depart safely.

Austin said the United States was not satisfied with how many people were being evacuated. “It’s obvious we’re not close to where we want to be in terms of getting the numbers through,” he said.

US troops guarding the evacuation effort fired some shots in the air overnight to control crowds, but there were no indications of casualties or injuries, the Pentagon said earlier on Wednesday.

Austin said there are about 4,500 US military personnel in Kabul and there “have been no hostile interactions with the Taliban, and our lines of communication with Taliban commanders remain open.”

Speaking to reporters alongside Austin, Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, said there had been no intelligence to indicate that the Afghanistan security forces and government would collapse in 11 days, as they did.

Milley said intelligence had “clearly indicated, multiple scenarios were possible,” including a Taliban takeover following a rapid collapse of Afghan security forces and the government, a civil war or a negotiated settlement.

“The timeframe of rapid collapse — that was widely estimated and ranged from weeks to months and even years following our departure,” Milley said.

The two top Republicans in the US Congress, Kevin McCarthy of the House of Representatives and Mitch McConnell of the Senate, requested a classified briefing for the “gang of eight” — the top eight relevant lawmakers — for a status report on the evacuation.

“It is of the utmost importance that the US government account for all US citizens in Afghanistan and provide the necessary information and means of departure to all those Americans who desire to leave the country,” they wrote in a letter to Biden.

Both Austin and Milley, who have served in Afghanistan, acknowledged that troops and veterans were finding the images from the evacuation troubling.

“I’m hearing strong views from all sides on this issue ... what’s important is that each of us will work our way through this in our own way,” Austin said. — CNN with input from agencies