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       People wait outside Hamid Karzai International Airport as a military transport plane takes off behind them in Kabul on Aug. 21.

       JIM HUYLEBROEK/The New York Times News Service

       The U.S. embassy in Kabul advised U.S. citizens not to travel to the Hamid Karzai International Airport at this time, according to an embassy security alert issued on Wednesday.

       Citizens already at the airport’s Abbey Gate, East Gate and North Gate were advised to leave immediately, the security alert said.

       Australia warns citizens to stay away from Kabul airport amid terror threat

       Last Kabul flight carrying Canadian nationals, Afghan refugees to leave Thursday, five days ahead of U.S. withdrawal deadline

       The alert, posted on the embassy website, gave no reason for why it was issued.

       It followed warnings by U.S. President Joe Biden and other administration officials of a threat by the Islamic State to evacuation operations as crowds thronged airport gates, desperate to leave following the Taliban takeover of Afghanistan.

       The alert advised Americans to “be aware of your surroundings at all times, especially in large crowds.”

       The Taliban have promised security outside the Kabul airport but intelligence reports of imminent threats cannot be ignored, a NATO diplomat said.

       The Associated Press reported that Britain and New Zealand also advised their citizens Thursday morning not to go to the airport, where there was a “very high threat of a terrorist attack.”

       Meanwhile, Australian Minister for Foreign Affairs Marise Payne said there is a high threat of a terrorist attack near the airport in Kabul on Thursday, as Canberra urged its citizens and those with a visa for Australia to evacuate the area.

       Australia has been evacuating its citizens and visa holders for more than a week from Kabul airport, where Canberra had urged people to travel in order to be ready for transport.

       Late on Wednesday, Australia changed its advice to those in the area, which Payne said was based on heightened concerns of an attack.

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       “There is an ongoing and very high threat of a terrorist attack,” Payne told reporters in Canberra.

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