The USA Today/Gallup Poll also revealed women -- a stronghold of support for the Democratic incumbent -- are moving toward the Republican challenger. Romney now holds a 12-point edge among men (54-42) who are likely to vote in the election and is even with Obama among likely female voters (48-48).
Among all registered voters surveyed, Obama held a 49 percent to 47 percent lead.
The poll of 1,023 registered voters, including 869 likely voters, was taken Oct. 5-11. Its margin of error was 4 percentage points.
The key states are Colorado, Florida, Iowa, Michigan, Nevada, New Hampshire, New Mexico, North Carolina, Ohio, Pennsylvania, Virginia and Wisconsin.