A US official says several Marines were killed and a number of other American military personnel were wounded in an attack on Kabul’s airport.
US officials have said that information is still coming in and they are trying to determine exact numbers of casualties.
The Pentagon would not say what troops were involved but acknowledged that “a number of US service members were killed”.
US Senate Majority Leader Chuck Schumer said that those responsible for the attack in Kabul “will be sought and brought to justice.”
The New York Democrat said in a statement that he had just spoken to Secretary of Defence Lloyd Austin about the “heinous attacks” on US personnel and the Afghan partners.
“I strongly condemn this act of terrorism and it must be clear to the world that the terrorists who perpetrated this will be sought and brought to justice,” he said.
Meanwhile, the US House Republican leader called on Speaker Nancy Pelosi to call the Congress back into session so lawmakers can consider legislation would prohibit the August 31 withdrawal until all Americans are out of Afghanistan.
Rep Kevin McCarthy of California said: “It is time for Congress to act quickly to save lives.”
A return to session before the deadline is highly unlikely. The Democrats aligned with President Joe Biden hold majority control and are not expected to consider such legislation to alter the withdrawal date.
Republicans have been highly critical of Mr Biden’s handling of the situation in Kabul.