WASHINGTON - A US soldier was killed while conducting operations against Islamic State in Afghanistan late on Saturday, a US military spokesman said in a message posted on Twitter. 'The soldier was mortally wounded late Saturday during an operation in Nangarhar Province' in eastern Afghanistan, US Navy Captain Bill Salvin said in a message on the official Twitter account of the NATO-led Resolute Support mission. The soldier was a Special Forces operator and was killed in the Achin district of Nangarhar province, Salvin told Reuters separately.