Vice-President Kamala Harris is expected to announce her running mate by Tuesday morning, ending two weeks of intense speculation as the US hurtles towards November's presidential election.

Ms Harris interviewed several top contenders in Washington DC over the weekend, including Josh Shapiro, Tim Walz and Mark Kelly.

Her choice will join her on a whirlwind five-day tour of seven cities this week as Ms Harris ramps up her campaign in key battleground states.

The most recent poll from CBS, the BBC's US partner, shows Ms Harris and Trump in a tight race nationally, with the Democrat holding a one-point lead over her Republican challenger.

The poll released on Sunday shows Trump and Ms Harris tied in battleground states, where the former president held a five-point lead while Joe Biden remained in the race.

Following the announcement expected on Tuesday morning, a campaign video will be released before Ms Harris and her new running mate jointly hold a rally in Philadelphia that evening.

She reportedly met her vetting team - led by former US attorney general Eric Holder - over the weekend and received in-depth presentations on their findings, including potential political vulnerabilities.

She met three of those candidates - Minnesota Governor Tim Walz, Arizona Senator Mark Kelly and Pennsylvania Governor Josh Shapiro - on Sunday.

She also met another top contender - Transportation Secretary Pete Buttigieg - on Friday and is understood to have spoken with other candidates virtually, US media report.

On Monday afternoon, in response to a report that Ms Harris had made her pick, a campaign spokesperson, Kevin Munoz, wrote on social media that she was still deciding.

"We understand the excitement and interest here, but VP Harris has made no decision on a running mate yet!" he said.

It comes as the DNC finished a virtual roll call vote that saw Ms Harris officially become the first black and South Asian American nominee for a major US party's White House campaign.

The Harris campaign has met with a flurry of lobbying efforts on behalf of - or criticising - the candidates.

Mr Shapiro, for example, has drawn sharp opposition from some left-wing groups for his support of private school vouchers in Pennsylvania - a Republican-backed proposal to send $100m to families for private school tuition and school supplies - as well as his pro-Israel views.

The Philadelphia event will be followed by a string of campaign events across Wisconsin, Michigan, North Carolina, Georgia and Arizona, before ending with a campaign event in Las Vegas, Nevada, on 10 August.

Trump and his running mate, JD Vance, have both suggested that Ms Harris' choice of running mate will ultimately have no impact on the upcoming election.

In an episode of the "Full Send" podcast aired on Friday, Mr Vance said he believed the vice-presidential choice "doesn't really matter, as much as this hits my ego".

"People are going to vote primarily for Donald Trump or for Kamala Harris," he said. "That's the way these things go."

Similarly, Trump has largely shrugged off questions about Ms Harris's choice, arguing last week that the vice-presidential role "does not have any impact".

On Sunday, however, Trump criticised Mr Shapiro on Fox News, saying that Ms Harris could lose "her little Palestinian base" if she chooses him.

Mr Shapiro, who during his student days wrote in a college magazine that Palestinians were "too battle minded", told reporters on Friday that he now supported a two-state solution.