Biden Vows Vengeance on Kabul Airport AttackersU.S. President Joe Biden is vowing vengeance on those responsible for Thursday's deadly attacks outside the Kabul airport that killed at least 13 American military personnel and dozens of civilians who had gathered there in hopes of fleeing the Taliban-controlled country. "To those who carried out this attack, as well as anyone who wishes America harm, know this: We will not forgive," Biden said in a nationally broadcast address. "We will hunt you down and make you pay." The Islamic State group claimed responsibility for the attacks in a report on its news agency's Telegram channel, hours after suicide bombers had struck two locations along the perimeter of the Hamid Karzai International Airport: near the Abbey Gate and outside a nearby hotel. A regional offshoot of Islamic State known as ISIS-Khorasan Province, or ISIS-K, has been blamed for the attacks. Biden said he had ordered commanders to develop operational plans to strike ISIS-K assets, leadership and facilities, saying, "We will respond with force and precision at our time, at the place we choose and the moment of our choosing." Shortly after the president's remark, the White House press secretary amplified his message: "We will hunt down these terrorists and kill them wherever they are." At least 90 Afghans died in the attack, according to the Afghan news agency Pajhwok. Including the 13 American servicemen, more than 100 people were killed. Eighteen injured American military personnel were being evacuated from Afghanistan on specially equipped C-17s with surgical units, according to Captain Bill Urban, a spokesman for the U.S. Central Command. A gun battle occurred after the bombings, U.S. General Frank McKenzie, head of U.S. Central Command, said during a Pentagon news briefing It was the deadliest day for the U.S. military in Afghanistan in a decade. That also made Thursday the most somber day of Biden's 7-month-old presidency, prompting the last-minute postponement of Biden's meeting with the visiting Israeli Prime Minister Naftali Bennett. During the gloomy afternoon, thunder echoed around the White House as a rainstorm enveloped Washington. The loss of life also intensified political flashpoints around the Democratic president, with several Republican members of Congress immediately issuing statements saying Biden bore personal responsibility and calling for him to resign. Joe Biden, Kamala Harris, Antony Blinken, Lloyd Austin and General Milley should all resign or face impeachment and removal from office. Biden has failed the American people as Commander-in-Chief and does not deserve the respect of that title any longer.\n\nSee my full statement on the tragic deaths of American marines in Kabul today --> pic.twitter.com/p3PetNyLwK "It's not a day for politics," replied Psaki, when asked about the resignation calls. "And we would expect that any American, whether they're elected or not, would stand with us and our commitment to going after and fighting and killing those terrorists wherever they live, and to honoring the memory of service members." More than 100,000 people have left Afghanistan on evacuation flights, Biden said Thursday, vowing the evacuations would continue until the August 31 deadline to withdraw all troops. "We will get Americans out who want to get out," the president said. Biden and Psaki said there was no evidence, so far, of collusion between the Taliban, which seized control of Kabul nearly two weeks ago, and ISIS in carrying out the attacks. The United Nations and NATO condemned the attacks, as did Taliban spokesperson Zabihullah Mujahid. Speaking about the first blast, a senior Taliban source confirmed to VOA that a suicide bomber had blown himself up in an area holding a large number of people. "The overall sense of mission is focused right now at the (passenger) terminal. Lots of Marines and consular officers cared deeply about the Afghans we were helping," said a U.S. State Department official who spoke to VOA on condition of anonymity. The U.S. is "trying to carry on with the mission ahead while knowing our security is severely compromised," the official said. "Attacks occurred right at our shift change; otherwise, consular officers might have been casualties, too." Many of those wounded Thursday arrived at Kabul's Emergency Hospital, run by an international nongovernmental organization that treats victims of war and landmines. Afghan news channels tweeted pictures of civilians transporting their wounded in wheelbarrows. In Pictures: People injured in explosion near Kabul airport pic.twitter.com/WQ8sdjvODG  Pakistan officials have asked that beginning Friday, hotels across the capital, Islamabad, cancel reservations and keep all rooms at the government's disposal for at least three weeks to accommodate the thousands of foreigners being urgently evacuated from Afghanistan. Biden on Thursday issued a proclamation lowering U.S. flags across the country through August 30 "as a mark of respect for the U.S. service members and other victims killed in the terrorist attack." Minutes later, the flag above the White House was lowered to half-staff. The flag has just been lowered here at the @WhiteHouse. pic.twitter.com/0T4o4g7fn1 Ayaz Gul, Ayesha Tanzeem, Carla Babb, Patsy Widakuswara contributed to this report.