The U.S. military said Monday that no American or NATO coalition forces were injured after a brief firefight broke out at one gate into Kabul's Hamid Karzai International Airport where troops are assisting with emergency evacuations of Western citizens and at-risk Afghan nationals.
Navy Capt. William Urban, a spokesman for U.S. Central Command, the combatant command that oversees American military operations in the region, said the incident "appeared to begin when an unknown hostile actor fired upon Afghan security forces."
The violence comes as the Biden administration grapples with a torrent of criticism over the fallout of its pullout from Afghanistan.
President Joe Biden said Sunday that the U.S. military has evacuated 28,000 people from Afghanistan since Aug. 14, but many thousands of Americans still remain there. The U.S. has a "long way to go and a lot could still go wrong," he told press from the White House, adding that, "The evacuation of thousands of people from Kabul is going to be hard and painful no matter when it started, when we began."
Urban on Monday described the firefight incident in Kabul. "The Afghans returned fire, and in keeping with their right of self-defense, so too did U.S. and coalition troops," he said, adding that one member of the Afghan forces was killed by the hostile actor and several Afghans were wounded during the exchange.
"The wounded are being treated at an airfield hospital and are reported to be in stable condition. Our condolences go out to the teammates and loved ones of the fallen Afghan soldier," he added.
The past week at Kabul's airport produced images of panic and desperation as mothers handed their babies to foreign soldiers over barbed-wire walls and Afghan civilians clung to airplanes as they took off in desperate attempts to flee their country since the Taliban take over.
The Pentagon said last week that the U.S. military could not ensure safe passage for Americans to Kabul airport, despite several thousand forces now being on the ground. And the U.S. Embassy in Afghanistan on Saturday warned American citizens not to travel to the airport due to security threats outside the gates.
On Sunday Biden activated the Civil Reserve Air Fleet, a rarely-used program whereby the Pentagon ordered civilian airlines to provide planes to help accelerate Afghanistan evacuation efforts. The activation is for 18 aircraft from six airlines.
The administration is considering extending the deadline for the complete troop withdrawal beyond its original Aug. 31 date, Biden added.
"Our hope is we will not have to extend, but there are going to be discussions, I suspect, on how far along we are in the process," he said.
But the Taliban will not extend the Aug. 31 deadline, according to reporting by Reuters citing two anonymous Taliban sources. The sources added that no Western authorities had contacted the group about extending the deadline.
Speaking to the press during a visit to Singapore on Monday, Vice President Kamala Harris said, "Right now we are singularly focused on evacuating American citizens, Afghans who worked with us and Afghans who are vulnerable, including women and children."
"We have a responsibility and we feel a deep commitment to making sure that folks who helped us are safe," Harris added, saying that there should be a "robust analysis of what happened" later.
Despite her assurances, Afghan staff working at the U.S. embassy in Kabul feel "deeply disheartened" by the U.S.'s evacuation efforts, according to a diplomatic cable seen by NBC News.
The Taliban, with which the U.S. had negotiated a cease-fire agreement, made a series of stunning gains across the country and finally seized the power center of Kabul on Aug. 15, taking essentially complete control of Afghanistan within roughly 10 days.
As a consequence, the Islamic extremist militants now have access to billions of dollars worth of American weapons surrendered by the Afghan military, which the U.S. trained and equipped for two decades.
And tens of thousands of Afghans have made desperate attempts to escape, particularly those who worked with U.S. personnel and fear reprisal killings by the Taliban. While Biden has said these Afghans will be supported, advocacy groups say that up to 20,000 remain in the country, unable to board an evacuation flight out due to bureaucratic barriers or lack of safe passage to Kabul airport.
CNBC's Natasha Turak contributed to this report from Dubai, and Amanda Macias contributed from Washington.