President Joe Biden on Thursday watched as the Afghanistan crisis spiralled from bad to worse when <a href="https://www.thenationalnews.com/world/asia/2021/08/15/afghanistan-live-updates-taliban-kabul/" target="_blank">13 US troops were killed</a> in a suicide bombing in Kabul, upending his claim that rushing to end America's longest war would save US lives. The ISIS-claimed attack means Mr Biden has now presided over the first US combat fatalities in Afghanistan since February 2020, and the deadliest day since 2011, when 31 Americans — including 23 Navy SEALs — were killed alongside seven Afghan partners when their helicopter was shot down. In a briefing at the White House, Mr Biden described the fallen US troops as "heroes" and said he would authorise strikes against those behind the attack. "I have also ordered my commanders to develop operational plans to strike ISIS-K assets, leadership and facilities," he said, referring to the Afghanistan ISIS affiliate. "We will respond with force and precision at our time, at the place we choose and the moment of our choosing." Bellicose talk of new military action comes days before Mr Biden's August 31 <a href="https://www.thenationalnews.com/world/uk-news/2021/08/24/kabul-evacuation-why-is-august-31-deadline-so-vital/" target="_blank">deadline to fly out all US citizens,</a> troops and Afghan allies. Chaotic scenes playing out at the airport even before Thursday's attack have left the president facing withering criticism from Democrats and Republicans alike. “This tragedy should never have been allowed to happen, which makes our grief even deeper and more difficult to understand,” former US president Donald Trump and his wife Melania said in a statement. Even as it became clear thousands of people will be left behind come September 1, Mr Biden ignored pleas from western and Nato allies — including<a href="https://www.thenationalnews.com/world/europe/2021/08/25/germanys-merkel-we-cant-abandon-afghans-after-august-31/" target="_blank"> at an emergency G7 summit this week</a> — to allow them more time to bring their people home. In his remarks on Thursday, Mr Biden reiterated the US will not change the deadline. Bradley Bowman, senior director at the Foundation for Defence of Democracies think tank, said the attacks would probably be perceived by Mr Biden as “a shot across the bow” by whoever was responsible. It will “reinforce their incentive to get out by August 31, based on the assumption that we will see more of this if we stay,” Mr Bowman told <i>The National</i>. On Wednesday, Mr Biden had argued that each passing day in Afghanistan brings increased risks to the thousands of US troops stationed at the Hamid Karzai International Airport. “Every day we're on the ground is another day we know that ISIS-K is seeking to target the airport and attack both US and allied forces and innocent civilians,” Mr Biden said. Top Senate Republican Mitch McConnell said the attack served as "the clearest possible reminder that terrorists will not stop fighting the United States just because our politicians grow tired of fighting them". As Thursday's events played out on monitors in the White House's Situation Room, Mr Biden's aides tore up his planner and shelved a meeting he had scheduled with Israel's<a href="https://www.thenationalnews.com/world/us-news/2021/08/26/israeli-pms-first-meeting-with-biden-postponed-due-to-afghanistan-violence/" target="_blank"> Prime Minister Naftali Bennett. </a> The Taliban have said they would allow Afghans to exit Kabul after August 31, but in the absence of western forces, it is anyone’s guess what will happen after that date. The Association of Wartime Allies reported that at least 250,000 Afghans who could qualify for US visas remain in Afghanistan, along with family members — far more than the US and other countries can bring out in the coming days. So far, the largest airlift operation in US history has flown about 101,000 people out of Kabul. Secretary of State Antony Blinken estimated on Wednesday that about 1,500 Americans were still in Afghanistan, along with other foreigners. Also on Thursday, a bipartisan group of 58 <a href="https://www.thenationalnews.com/world/us-news/2021/08/24/us-congressional-leaders-urge-biden-to-extend-afghanistan-withdrawal/" target="_blank">members of Congress called on Mr Biden to extend the evacuation deadline</a>, arguing it “does not provide enough time to evacuate all American citizens and our partners". Mr Biden has argued that the quick Taliban takeover of Afghanistan and the collapse of the US-backed military was proof he had made the right decision in ending the war. Staying in Afghanistan would mean he would have to “send your sons, your daughters — like my son was sent to Iraq — to maybe die. And for what? For what?” he asked on August 20.