US President Joe Biden arrived at Dover Air Force Base on Sunday to honour members of the military killed in a bomb attack during the evacuation of civilians from Afghanistan last week.
An IS suicide bombing on Thursday killed scores of Afghans and 13 American troops who were guarding Kabul's airport amid an airlift that has evacuated about 114,400 people in the past two weeks.
After arriving at the base in Delaware, Biden and his wife, Jill, met with the families of service members killed in the attack.
They watched as flag-draped cases carrying 11 service members' remains were loaded into vans.
The sounds of crying could be heard and one woman collapsed and was taken to an ambulance. After the event, a woman let out anguished screams.
The remains of two more service members will be transferred in an event not covered by media at the request of their families.
Thursday's attack, which was claimed by ISIS-K, the Afghan affiliate of IS, was the most lethal incident for US service members in Afghanistan in a decade.
The bombing took place just outside the gates of the airport, where thousands of people have gathered to try to get a flight out of the South Asian nation since the Taliban returned to power on August 15.
American forces launched a military strike in the Afghan capital on Sunday targeting a possible suicide car bomb, US officials said.
"We are in a period of serious danger given what we are seeing in the intelligence," Biden's national security advisor, Jake Sullivan, told CNN’s "State of the Union" programme in an interview broadcast on Sunday, before the latest strike was reported.
"We are taking every possible measure at the direction of the president to ensure that our forces are protected on the ground even as they complete their mission of bringing in the remaining American citizens and Afghan allies."
Biden, a Democrat, faced criticism from Republican lawmakers, who accused his administration of bungling the withdrawal of US forces from Afghanistan.
The Taliban's rapid advance across Afghanistan amid the withdrawal of American and allied troops combined with the chaotic scenes at the airport have presented Biden with his biggest foreign policy challenge as president.
Biden has vowed to punish those responsible for the airport bombing. The US military said on Saturday that it had killed two ISIS-K militants in a drone attack in eastern Afghanistan.
Sullivan said the two "are individuals involved in the facilitation and planning and production of explosive devices and they are part of the larger network of ISIS-K."