Two NATO soldiers were killed in separate attacks in Afghanistan, the alliance said Sunday as the alliance's biggest-ever operation in the south of the country entered its second week, with Taliban showing "determined resistance". One of the soldiers was killed in roadside bomb blast in southern region, while the other died in indirect fire in country's east, dpa quoted the NATO military as saying in statements. It did not disclose the nationalities of the soldiers, but said they did not die during Operation Mushtarak that began against one of the main Taliban bastions in southern Helmand province last week. NATO said the offensive, the largest since the ouster of the Taliban regime in a US-led invasion in late 2001, was "on track" as the combined Afghan, US and British forces were making progress through Marjah, a town in Nad Ali district. The area that is located some 20 kilometres from the provincial capital Lashkargah, is the main opium producing region in Afghanistan. A total of 15,000 Afghan and NATO troops have taken part in the operation, aimed at extending the Afghan government's authority in the province's central region and trying to win the hearts and minds of locals by launching reconstruction projects. Some sixteen civilians have been killed since last Saturday, along with 12 NATO troops, an Afghan soldier and more than 40 Taliban militants.