THE top US commander in Afghanistan has admitted that the Taliban have gained the upper hand in the country, forcing the US to change its strategy in the eight-year-old conflict by increasing the number of troops in heavily populated areas like the volatile southern city of Kandahar, the insurgencys spiritual home. Gen Stanley McChrystal, the US commander in Afghanistan, warned that means US casualties, already running at record levels, will remain high for months to come. In an interview with The Wall Street Journal, Gen McChrystal offered a preview of the strategic assessment he is to deliver to Washington later this month, saying the troop shifts are designed to better protect Afghan civilians from rising levels of Taliban violence and intimidation. The coming redeployments are the clearest manifestation to date of Gen McChrystals strategy for Afghanistan, which puts a premium on safeguarding the Afghan population rather than hunting down militants. Gen McChrystal said the Taliban are moving beyond their traditional strongholds in southern Afghanistan to threaten formerly stable areas in the north and west. The militants are mounting sophisticated attacks that combine roadside bombs with ambushes by small teams of heavily armed militants, causing significant numbers of US fatalities, he said. Its a very aggressive enemy right now, Gen McChrystal said in the interview at his office in a fortified Nato compound in Kabul. Weve got to stop their momentum, stop their initiative. Its hard work. In an effort to regain the upper hand, Gen. McChrystal said he will redeploy some troops currently in sparsely populated areas to areas with larger concentrations of Afghan civilians, while some of the 4,000 American troops still to arrive will be deployed to Kandahar. Gen McChrystals predecessor, Gen David McKiernan, had a request outstanding for 10,000 more troops. Gen McChrystal said he had not decided whether to request additional US forces. Were still working it, he said. Gen McChrystal also said he would direct a very significant expansion of the Afghan army and national police - which would double in size under the plans being finalized by senior U.S. military officers here - and import a tactic first used in Iraq by moving US troops onto small outposts in individual Afghan neighbourhoods and villages. Gen McChrystal said in the interview that he planned to shift more US troops to Kandahar to bolster the Canadian forces that currently have primary security responsibility for the region. Its important and so were going to do whatever we got to do to ensure that Kandahar is secure, he said. With the arrival of the new US forces well have the ability to put some more combat power in the area. Gen McChrystal defended the decision to focus first on Helmand. The current operation, one of the largest since the start of the war in 2001, was meant to disrupt the Talibans lucrative drug operations there, he said. He said his new strategy had to show clear results within roughly 12 months to prevent public support for the war from evaporating in both the US and Afghanistan. This is a period where people are really looking to see which way this is going to go, he said. Its the critical and decisive moment.