Democratic presidential hopeful Barack Obama said Afghanistan might end up being tougher to subdue than Iraq, days after visiting both war zones. The White House hopeful told Time magazine in an interview that his two trips had confirmed in his mind many of his earlier thoughts about future US policy towards the two countries. "I think in Afghanistan, looking at the landscape and the extraordinary poverty involved, makes you realise what a daunting task our efforts there are going to be," Obama told Time. "It redoubles my belief, or deepens my belief, that if we're going to get that done we're going to have put in more resources," he said in the interview. The Illinois senator has laid out a plan to start withdrawals of combat troops from Iraq as soon as taking office, and would hope to get most US soldiers out of the country within 16 months.