WASHINGTON (AP) — Support for the war in Afghanistan has reached a new low, with only 27 percent of Americans saying they back the effort. And about half of those who oppose the war say the continued presence of American troops in Afghanistan is doing more harm than good.

That's according to an AP-GfK poll released Wednesday that found 66 percent opposed to the war.

A year ago, 37 percent favored the war. In the spring of 2010, support was at 46 percent.

The poll found that 27 percent, far less than last year, think the killing of Osama bin Laden by U.S. troops increased the threat of terrorism against Americans.

The poll was conducted before this week's revelation of a recent al-Qaida plot to blow up a U.S.-bound airliner.