Harris, who last visited the border in 2021, accused Donald Trump of being focused on “scapegoating instead of solutions” and “rhetoric instead of results”.

Earlier on Friday, the Republican nominee argued Harris was “getting killed” on the issue and supports “the worst bill ever drawn” on border security.

Polls suggest more Americans trust Trump over Harris on handling the border and illegal immigration.

Cochise County, a conservative stronghold in Arizona that became a hot spot for record-high border crossings last autumn, provided a backdrop for the Democratic nominee to inspect the border wall, speak with local officials and project a message of toughness.

She claimed Trump “did nothing to fix our broken immigration system” as president, adding that Republicans were trying to force a “false choice” between border security and a “safe, orderly and humane” immigration system.

“We can and must do both,” she told supporters at a campaign event in Douglas.

Harris vowed to further toughen asylum laws enacted earlier this year by President Joe Biden and to revive a bipartisan border security measure Trump helped block.

But Jim Chilton, a local rancher, said he has “seen the evidence” of what Harris would do in power.

“I’ve watched her and President Biden,” he told the BBC. “We’ve had an open border policy. We now are understanding what that really means.”

Every year, thousands of undocumented migrants walk through Mr Chilton’s 50,000-acre ranch just south of Arivaca.

He has motion-activated cameras that show the procession of people, all dressed in near-identical camouflage, across his land. He is convinced drug dealers and gang members are among them.

Menacing signs threaten trespassers with death, but Mr Chilton has also installed drinking fountains so nobody dies making the hazardous journey.

Three corpses were found on his land last year.

A Trump supporter, Mr Chilton does not believe Harris will crack down on the flow of migrants.

“She’s changing her mind just to get votes and lie to us. It’s outrageous,” he said.

Concerns over stemming the influx are ever present in tiny border towns like Douglas.

Homeowners here can see through miles of border fencing into Mexico when they step out onto their front porches.

One woman said her neighbours built brick walls around their homes to keep migrants from hiding out in their backyards.

Even some Democrats here who are voting for Harris said they preferred Trump’s border approach and felt safer during his tenure.

Last year, a handful of churches and the town’s visitor centre transformed overnight into makeshift shelters to house newcomers.

Since then, the Biden administration has enacted tougher restrictions on seeking asylum and migrant crossings have plunged to four-year lows.

Gail Kochorek is a dedicated volunteer who drives down to the wall to hand out food and water to people on the Mexican side, usually waiting until after dark to cross back into the US.

To her, the political approach to immigration is increasingly dehumanising to people hoping to making a better life in her country.

She is disappointed to hear Harris promising to crack down on migrants but, given a choice between her and Trump, the Democrat can count on Ms Kochorek’s vote.

Laughing at Trump’s pledges to secure the border, she showed the BBC gaps in Trump’s wall and where people could cut through the steel fencing.

The former president has vowed to seal the border by completing construction of the barrier, increasing enforcement and implementing the largest mass deportation of undocumented migrants in US history.

But earlier this year, he urged Republicans to ditch a hardline, cross-party border bill that was endorsed by Biden and Harris.

“That’s the worst bill ever drawn. It’s a waste of paper,” Trump told supporters earlier on Friday at a rally in Walker, in the swing state of Michigan.

Denying that he lobbied congressional allies to tank the piece of legislation, Trump claimed Harris “want to see if she could salvage it and make up some lies”.

“She went to the border today because she’s getting killed on the border,” he said.

In a statement following Harris’s event, the Trump campaign characterised the visit as a “drop-in” and “photo op”.

The border crisis has been a major vulnerability for Harris.

As vice-president, she has not directly shaped border policy but was put in charge of addressing the root causes of migration from the Northern Triangle countries of Guatemala, El Salvador, and Honduras.

Her efforts targeted systemic issues like poverty, corruption, and violence, which for years have driven large numbers of people from these regions to make the treacherous journey to the United States.

It is too soon to tell if the two-part strategy – bolstering democratic institutions and coaxing business leaders to invest in the region – is working, but Harris has taken a lot of blame for upward trends in migration.

As a candidate, she has highlighted her experience as a prosecutor when she was attorney general of California, particularly in investigating transnational and cartel organisations, to emphasise her approach to tackling immigration-related challenges.

Her recent remarks have aligned closely with Biden’s emphasis on border security and law enforcement, but also reflect how the politics of the issue have shifted notably to the right.

As she seeks to convince voters that she has a plan, her biggest challenge is finding an approach that balances the legal and humanitarian aspects of the immigration system.