In another tragic incident, NATO says five civilians have been accidentally killed and two wounded by an air strike in Kandahar province, east off the Marjah offensive. They were mistakenly believed to have been planting roadside bombs.

Meanwhile, Taliban fighters stepped up their counter-attacks against Marines and Afghan soldiers in Marjah. Although the Afghan government claims the insurgents are broken and on the run, their attacks have actually slowed the allied advance to a crawl.

An Afghan commander in the south, told reporters in nearby Lashkar Gah that there had been "low resistance" in the town which would soon be cleared of militants.

However, small, mobile teams of insurgents repeatedly fired on US and Afghan troops.

An Afghan National Army (ANA) loads his machine gun before leaving a camp in Lashkar Gah in Helmand province on the third day of a joint operation Mushtarak.