KABUL (AFP) - An Afghan civilian was killed by foreign soldiers who mistakenly thought he was running towards them with a bomb during a major assault against militants in Southern Afghanistan, NATO said Saturday. The incident happened on Friday in Nad Ali which, along with Marjah, is the focus of a massive US-led military operation in Helmand province, NATOs International Security Assistance Force (ISAF) said in a statement. Some 15,000 NATO and Afghan troops led by US Marines are involved in Operation Mushtarak, which aims to clear militants from the areas of the central Helmand River valley they have controlled for at least two years. Provincial spokesman Daud Ahmadi told AFP that 15 civilians have been killed since the operation began on February 13. It was not clear if the figure included the death reported by ISAF. A civilian was killed in Nad Ali yesterday morning after an ISAF patrol believed he was carrying an IED toward them, the ISAF statement said, referring to crude bombs known as improvised explosive devises.