Some 41% of the 833 registered voters in a nationwide survey online said they would vote for Biden if the election were held today, compared with 37% for Trump.

That 4 point lead was up from a 1 point lead Biden held in a Reuters/Ipsos poll in March.

The poll also showed that many voters remain on the fence, with some 22% of registered voters in the poll saying they had either not picked a candidate, were leaning toward third-party options or might not vote at all.

Biden had a smaller lead of just 1 point among all respondents, but his lead among registered voters is significant, as people who are already registered to vote are more likely to cast a ballot in November.

The poll included many ways to measure candidate support- most pointing to a close race.

Nationwide surveys give important signals on American support for political candidates.

However, just a handful of competitive states typically tilt the balance in the U.S. electoral college, which ultimately decides who wins a presidential election.