US soldiers assist with security at an evacuation control checkpoint [Victor Mancilla/US Marine Corps via AP]

Kabul, August 23 (RHC)-- An Afghan security guard has been killed in a firefight between unknown gunmen and Afghan forces at the north gate of Kabul airport, the German military said, as thousands thronged the airport, seeking to flee Taliban rule.

Three more people were injured in the gun battle on Monday morning that has also involved German and United States forces, the German military said on Twitter.

The airport has been the scene of chaos since the Taliban seized the Afghan capital on August 15 as US and international forces try to evacuate citizens and vulnerable Afghans. A NATO official has said that at least 20 people have died in and around the airport in the past week.

U.S. President Joe Biden has stated that the “hard and painful” airlift of Americans and tens of thousands of others from Afghanistan’s capital is accelerating, but he would not rule out extending it beyond the August 31 deadline he set before the Taliban’s swift takeover.