The Oct. 21-27 opinion poll shows 42 percent of people who either voted already or expect to vote in the Nov. 8 election support Clinton, versus 36 percent for Trump. Clinton's lead a week ago was 4 points.
The polling was conducted before Clinton's campaign was hit on Friday by the FBI announcement that it was investigating more emails as part of a probe into her use of a private email server while secretary of state.
FBI Director James Comey said in a letter to several congressional Republicans that the agency had learned of the existence of emails that appeared to be pertinent to its investigation. However, he said the FBI did not know if the emails were significant and did not provide a time frame for the probe.
Trump, a New York businessman seeking his first elected office, has consistently trailed Clinton in the poll. His level of support has remained below 40 percent among all likely voters since the beginning of September.
Clinton leads Trump by 10 points among likely women voters, up from a 4-point lead the previous week. Clinton has led Trump among women over the last two months, though the size of her advantage has varied widely from 1 point to 11 points.
In a 2005 video that emerged this month, Trump could be heard bragging in vulgar terms about groping and kissing women. At least a dozen women have since publicly accused him of making unwanted sexual advances. Trump denies the allegations.
Trump still has an edge among white women, a key source of strength for Republicans. Trump leads Clinton by 2 points with this group, down from a 12-point lead the previous week.
Women tend to lean Democratic, but Reuters/Ipsos polling this month shows a majority of women have an unfavorable view of the former US secretary of state and believe she is not honest and truthful.
Clinton also led Trump by 6 points in a separate Reuters/Ipsos poll that included alternative party candidates.
Both polls, conducted online in English in all 50 states, included 1,627 American adults who were considered to be likely voters from their voting history, registration status and stated intention to vote.
That sample included 965 likely women voters and 776 likely white women voters. Individual responses were adjusted to reflect the overall US population.
The poll has a credibility interval, a measure of accuracy, of 3 percentage points for the total sample and 4 percentage points for the women voters.
The RealClearPolitics website, which tracks most major polls, shows Clinton leading Trump by an average of 5 percentage points.
