WASHINGTON (CBS News) — Thirteen U.S. service members were killed and more than a dozen others injured in an attack outside the airport in the capital of Afghanistan on Thursday, opening a deadly new chapter in the massive U.S. effort to evacuate Americans and Afghan allies ahead of President Biden’s August 31 deadline to withdraw.

The Pentagon said a suicide bomber detonated an explosion that tore through a crowd waiting at an entrance to the Hamid Karzai International Airport in Kabul, where thousands of people have gathered every day since the city fell to the Taliban, desperate to board flights out of the country. Another explosion struck a nearby hotel, the Pentagon said.

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The total death toll stood at 90 people as of Thursday evening, with 150 more wounded, an Afghan official said. The tally was expected to climb.

At the remarks at the White House later in the day, the president said the bombings were the work of fighters from the ISIS affiliate in Afghanistan, known as ISIS Khorasan, or ISIS-K. The attacks marked one of the single deadliest days for U.S. forces in Afghanistan in the 20 years since the allied invasion.