Moreover, the Washington Post-ABC News poll indicated public approval of Obama's handling of the situation has fallen.
Forty-seven percent of those asked said they favor the buildup requested by Gen. Stanley McChrystal, the top U.S. commander in Afghanistan, while 49 percent said they oppose it, pollsters said.
A majority of respondents -- 63 percent -- said the administration doesn't have a clear plan for addressing the problems in Afghanistan, the poll said.
As Obama deliberates troop deployment and strategy in Afghanistan -- the White House said a decision could be reached within the next few weeks -- approval of his leadership on the Afghan war has slipped since the spring, results indicate. In April, Obama received a 63 percent approval rating for his handling of the war in Afghanistan. In the latest Washington Post-ABC News poll however, 45 percent of respondents approve, down 10 percentage points in the past month alone, while 47 percent said they disapprove, an increase of 10 points.
The poll indicated 57 percent of those questioned approve of how Obama is carrying out his presidential duties overall.
The nationwide telephone poll surveyed 1,004 adults Thursday through Sunday. The margin of error is 3 percentage points.