Washington, Aug 17 (IANS): Presumptive Democratic presidential nominee Joe Bidens lead over President Donald Trump has narrowed since last month, according to a new national poll.

Biden leads Trump by just 4 points, with the former Vice President at 50 per cent and the latter at 46 per cent, The Hill news website quoted the CNN poll as saying on Sunday.

This marks a significant shift since the poll was last conducted in June, when Biden led Trump by 14 points at 55 per cent and the President at 41.

The movement in the poll among voters is concentrated among men, who were split about evenly in June but who now back Trump over Biden 56 to 40 per cent, and voters between the ages of 35 and 64, who tilt toward Trump now but were leaning toward Biden in June, according to CNN.

Voters who said they back Trump, though, are more likely to say they may change their mind.

Twelve per cent of voters who said they back Trump said they may change their mind before Election Day, but just 7 per cent of Biden supporters said the same, based on the poll.

The results of the national survey come just ahead of the Democratic National Convention, which begins on Monday, The Hill news reported.

A range of Democrats are scheduled to speak as part of the virtual programming to boost Biden as the is set to accept the party's nomination.

Other recent polls, including an NBC News-Wall Street Journal poll released earlier on Sunday, have found Biden with a wider lead over Trump.

Recent polls of key battleground states have also indicated Biden has a lead over the President.