Support for the war in Afghanistan has fallen to an all-time low in the United States, according to a national poll published Tuesday by CNN on Tuesday. Fifty-seven per cent of 1,010 Americans questioned in a CNN/Opinion Research Corporation survey said they opposed the war, while 42 per cent backed the mission. The number of respondents against the war is up by 11 percentage points since April and was the highest in a CNN poll since the conflict began in October 2001. It also found that only 40 percent of interviewees said they believed the war is winnable. President Barack Obama has identified Afghanistan as a top priority, and his administration is reviewing the situation as it weighs a new strategy. US, NATO and Afghan forces are facing resurgent Taliban militants, who have grown in strength in the last two years years and have continued to inflict heavy casualties on US-led NATO forces. The US military death toll in recent months has been among the highest since the beginning of the war, as offensive efforts have been stepped up in areas with Taliban activity. Meanwhile, Obama's job approval rating has continued to slide. His overall rating slipped by 3 points to 53 in the CNN poll. For the first time since he took office in January, a majority of independent voters disapprove of the job he has done so far. Obama finds himself in a tough fight with Congress over health- insurance reform and has seen some of his own centre-left Democrats in Congress drop their support for his health plan.