Afghanistan updates: Chaos at Kabul airport, world responds

United States troops have taken control of the airport in Kabul, Afghanistan, as chaos continues after the Taliban seized control of the country.

A U.S. official told Reuters that U.S. troops have fired shots into the air to prevent civilians from running onto the tarmac at Hamid Karzai International Airport in Kabul, where scenes on the ground show an increasingly panicked people.

"The crowd was out of control. The firing was only done to defuse the chaos" and prevent the crowd from storming the runway," the official told Reuters.

U.S. troops have reportedly established large barriers and roadblocks on the streets near the airport in an effort to both slow and control the fleeing population.

White House National Security Adviser Jake Sullivan stuck to the administration's messaging on ABC's "Good Morning America" on Monday and placed blame for the speed of the Taliban takeover on the Afghan army for its decision "not to step up and fight for their country."

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"What the president was not prepared to do was enter a third decade of conflict, flowing in thousands of more troops, which was his only other choice, to fight in the middle of a civil war that the Afghan army wouldn't fight for itself," Sullivan said. "He would not do that to America’s men and women or their families, and that is why he made the decision to withdraw U.S. forces from Afghanistan this year."

As with Pentagon officials, Sullivan would not say that the takeover took the administration by surprise but, presented with the fact that thousands of allies appear stranded in the country, said the U.S. had planned for a "wide range of contingencies."

"We believe that we can effectuate an ongoing evacuation of American citizens, of Afghans who worked for us, including interpreters and translators and others vulnerable Afghans at risk. We're working to do that by securing the airport today and in the days ahead by taking people out one flight at a time, flight after flight," Sullivan said.

Sullivan insisted Afghanistan presented the U.S. an opportunity to prove "that we can fight terrorism effectively having without a large military footprint on the ground."

He also said the American people can expect to hear from the president "soon" as President Joe Biden faces criticism from lawmakers on both sides of the aisle and the public for how the withdrawal has played out.

The world reacts
An emergency session of the United Nations will be held Monday, and leaders around the globe have been issuing responses to the Taliban takeover of Afghanistan.

British Defense Secretary Ben Wallace was speaking about the race against time to evacuate Brits and Afghans who helped the military when he became overcome with emotion after saying that some people who served the U.K. will not come back.

When asked in an interview with British radio station LBC why he was taking it so personally, he said, "Because I'm a soldier. It's sad, and the West has done what it's done, and we have to do our very best to get people out and stand by our obligations."

Russia’s top envoy on Afghanistan has said Moscow will not rush to recognize the Taliban as the country’s new government.

But the envoy, Zamir Kabulov who oversees Russia’s Afghan policy, said in a radio interview with Echo of Moscow the Taliban had learned its lesson from 20 years ago when the world moved against them as terrorists.

He said the Taliban had promised no Russians would be harmed and that the group’s fighters have now taken Russia’s embassy under protection in Kabul. Russia has not evacuated its embassy so far, though it has pulled out some staff.

Meanwhile, official statements from China lay the groundwork for Beijing recognizing a Taliban government.

Spokesperson Hua Chunying noted that the Taliban said Sunday that the "war in Afghanistan is over" and that they will work to establish an inclusive government and ensure the safety of foreign missions in Afghanistan. Chunying said China expects these statements to be implemented in order to ensure a smooth transition and curb terrorist and criminal acts, so the Afghan people can avoid war and rebuild their country.

China has been wanting to expand their Belt and Road infrastructure initiative into Afghanistan but the U.S.-backed government had been reluctant to commit. China is connected to Afghanistan by a sliver of land called the Wakhan Corridor, which has historically been a well-traveled trade route. It connects to China's Xinjiang region, and if it were opened, it would provide a better route from Kashgar, China, to Peshawar, Pakistan.

ABC News' Julia Macfarlane, Patrick Reevell and Karson Yiu contributed to this report.