Berlin, Aug 23 :German and US forces joined in a gun battle Monday at Kabul airport after Afghan guards and unknown assailants exchanged fire, with one guard killed, the German army said.

 “This morning at 4.13am, there was an exchange of fire between Afghan guards and unknown assailants at the North Gate of Kabul airport. An Afghan guard was killed, three others injured,” said the German army on Twitter, adding that its forces and American counterparts “participated in further exchange of fire.”