Analysts agreed that polls five months before the election may not be indicative of the final outcome but would be watched closely by the candidates.

In the CNN/Opinion Research Corporation poll, the first conducted entirely after Obama became the presumptive Democratic nominee, he leads his Republican counterpart 49 per cent to 46 per cent among registered voters -- a statistical tie, given the 3-point margin of error.

McCain and Obama are not alone. Independent candidate Ralph Nader and Republican-turned-Libertarian Bob Barr are vying with the two major-party candidates for independent voters.

But at this point, the poll says it looks unlikely either will play a spoiler role. When pollsters asked about a field of candidates that includes Nader and Barr, the margin between Obama and McCain was virtually unchanged, with Democrat leading 47 per cent to 43 percent. Nader pulls in 6 per cent and Barr 2.