Live Updates: Pentagon confirms explosion outside Kabul airport

Washington — The Pentagon confirmed Thursday morning that an explosion occurred outside the main airport in Kabul, where the U.S. military has been working to evacuate scores of American citizens and at-risk Afghans from the country ahead of President Biden's August 31 deadline to complete the withdrawal of American forces from Afghanistan.

Pentagon press secretary John Kirby said on Twitter casualties from the blast are "unclear at this time," and the Defense Department "will provide additional details when we can." A White House official told CBS News that Mr. Biden has been briefed on the explosion.