The soldier was on a routine patrol Saturday with members of the Afghan national army in the Nahr-e Saraj district of Helmand province, the ministry said in a statement.
The patrol came under light arms fire and the soldier received a fatal gunshot wound.
It said an investigation had been opened to check out a report that the fatal shot had been fired by an Afghan soldier.
On Saturday NATO`s International Security Assistance Force (ISAF) announced that a man wearing an Afghan army uniform opened fire on two NATO troops in southern Afghanistan, killing one of them.
Dozens of foreign troops have been gunned down by renegade police and soldiers or insurgents disguising themselves as Afghan security forces.
London currently has around 9,500 soldiers deployed in the NATO force in Afghanistan, the biggest contingent after the United States.
Earlier this month Britain announced it would withdraw a further 500 troops from Afghanistan by the end of next year, but would keep soldiers there in a training role until at least 2023.
In June US President Barack Obama announced a big drawdown of US forces in the war-torn country.
(Uu.B002)
Editor: Priyambodo RH
Copyright © ANTARA 2011
