Polls show Harris gaining strength against Trump as race becomes more competitive

Kamala Harris has continued to gain strength in the US presidential election, as polls nationally and in battleground states show her building leads or catching Donald Trump.

- Martin Pengelly, Chris Stein

Yesterday morning, FiveThirtyEight, a leading polling analysis site, put Harris, the Democratic party's presumptive nominee for president, up by 2.1 points over her Republican rival in its national average.

In averages for swing states, where control of the White House rests, Harris led in Michigan by two points, Pennsylvania by 1.1 and Wisconsin by 1.8. Trump led in Arizona by less than half a point and in Georgia by half a point.

In battleground states without enough polls to calculate averages, Trump was ahead by about three points in North Carolina, and the candidates were about level in Nevada - where recent CBS and Bloomberg polls gave Harris two-point leads.

The US vice-president, 59, has changed the election race since midJuly, when Joe Biden, 81, heeded calls from his own party to step aside, allowing a younger candidate to take on Trump, who is 78. He endorsed Harris to take over the top of the Democratic ticket for this November, while he serves out his single term.

Harris will have the change to reintroduce herself to the public in a face off with Trump for the first time in a televised debate on 10 September, ABC News confirmed on Thursday.