Four NATO-led US soldiers were killed in two roadside bomb blasts in southern Helmand province, an alliance military spokeswoman said Sunday, according to dpa. The US service members were killed on Saturday in two separate incidents in southern Helmand province, where a major anti-Taliban assault involving nearly 5000 Afghan forces and US Marines is ongoing, a NATO spokeswoman in Kabul told German Press Agency dpa. NATO-led International Security Assistance Force (ISAF) also confirmed the deaths of the soldiers in a statement, but did not reveal the nationalities of the soldiers. Southern Helmand is the main hub for Taliban insurgents, whose government was toppled in a US military invasion in late 2001. Fifteen British soldiers were killed in the province in the past ten days, taking the total number British servicemen killed in Afghanistan since their deployment in late 2001 to 186. More than 8,300 British soldiers are stationed in Helmand. The ISAF statement also said a fifth soldier succumbed to injuries sustained in combat in Afghanistan last month. The soldier died on July 10 in his home country, it said, but did not disclose his nationality.