Five Afghan children were killed in a firefight involving Australian troops, while a US-led coalition soldier died in Afghanistan, officials said, as the new US envoy held talks in Kabul Friday. The Australian defence department said soldiers were conducting "clearance operations" in militant compounds in the southern province of Uruzgan on Thursday when they were fired on by Taliban rebels and returned fire. "No Australians were injured in the engagement, but a number of people have been killed and wounded during this incident," its statement said. "Current reporting indicates that those killed include a suspected insurgent and, sadly, local nationals, including five children killed, and two children and two adults injured."