LASHKAR GAH, Afghanistan, (Agencies) Taliban militants are digging in ahead of a major Nato operation in Helmand province in southern Afghanistan, in one of the biggest offensives in the eight-year-old war. The commander of foreign forces in Afghanistan said the offensive will send a 'strong signal and clear insurgents from their southern stronghold, as residents fled ahead of the assault and American and British troops have begun targeting insurgent leaders for assassination. Military sources said Special Forces had been infiltrating the Taliban stronghold of Marjah on kinetic missions - jargon for armed attacks. Special forces guys have been going in on assassination missions with the aim of decapitating the Taliban force, one said. At the British base of Camp Bastion and the adjoining Camp Leatherneck, the US marine base, troops and munitions have been airlifted in by night to avoid enemy rockets. It is clear that international forces are on the brink of a big battle. US Marines are set to launch an operation within days to take Marjah, an area of lush farmland criss-crossed by canals in the centre of Helmand, Afghanistans most violent province. The offensive will be the first major show of force since President Barack Obama ordered in 30,000 extra troops. Some of the villagers escaping Marjah in fear of their lives said fighters are digging in rather than fleeing. The Taliban are not going to leave Marjah. We have seen them preparing themselves. They are bringing in people and weapons. We know there is going to be a big fight, said Abdul Manan, a man from Marjah who had fled to Helmands capital, Lashkar Gah. The Taliban are very active in Marjah. They are planting mines there and in the surrounding areas, said villager Abdul Khaleq after arriving in Lashkar Gah with his family. Abdullah Nasrat, a Taliban commander in Nad Ali district where Marjah is located, told Reuters by telephone there were some 2,000 insurgents there ready to fight to the death. We dont have sophisticated weapons like the Americans with tanks and airplanes, but we have Islamic zeal. That is the power we have to fight against the infidels, he said. Around 100 families have fled Marjah and surrounding areas, seeking refuge in Lashkar Gah over the last week, the provincial Governors spokesman Dawood Ahmadi said. Afghan families average around six members. Provincial officials said they were preparing to receive around 7,000 families - each averaging five members - as residents left Marjah and headed to the provincial capital Lashkar Gar and elsewhere in the province. Today alone, 85 families left Marjah with me, said Gul Muhammed as he put his goats on the back of a truck. US General Stanley McChrystal, who leads 113,000 US and Nato forces fighting the militants in Afghanistan, said Operation Mushtarak ('Together) will send a strong signal that the Afghan government is expanding its security control. As part of his counter-insurgency strategy emphasising development and governance, McChrystal said the Marjah operation was not about killing Taliban fighters but eradicating the militant threat. Whether fighters left the region or rejoined society - as President Hamid Karzais reconciliation programme encourages them to do - the aim was to establish Afghan civilian governance, he said. Were trying to make this not a military operation only, but a civilian and military operation because the thing that is changing is not just going to be the level of security in the area but the governance, McChrystal said. So all the planning for this operation has been led by the civilian side with the military in support - and of course this is an Afghan-led operation.