Kamala Harris is set to visit the southern US border for the first time in three years in an attempt to confront her electoral vulnerabilities on immigration.

The US vice-president will view a port of entry between Mexico and the battleground state of Arizona later on Friday afternoon before holding a rally in the border town of Douglas.

Campaign aides said the Democratic presidential candidate will use the visit to attack Donald Trump on an issue that has been central to the Republican’s campaign, and a major weakness of her own.

She is expected to highlight the former president’s role in tanking legislation put forward by a cross-party group of senators that was hailed as the toughest bipartisan border security plan in a generation.

It marks her first visit to the southern border since June 2021, and only her second as vice-president, despite being tasked by Joe Biden with stemming the flow of migrants from Latin America into the US early in his term.

Ms Harris has struggled with the brief and, while it does not include oversight of the physical border, the Trump campaign has used it to brand her a “failed border tsar”.

Her first border visit in 2021 followed intense political pressure amid an unfolding crisis, with border facilities overrun and asylum seekers being held in squalid conditions.

When Ms Harris was asked why she had not yet visited the border in an interview at the time, she replied: “I haven’t been to Europe [either]”.

It was seen as a PR disaster and her trip to El Paso, Texas, followed shortly afterwards.

Conditions on the southern border have since improved, with shelters seeing a sharp decline in numbers and official data over the summer recording the number of apprehensions is at the lowest level since Mr Biden entered office.

However, immigration remains an electoral millstone for Ms Harris’ White House run, with polls consistently showing voters trust her far less than Trump on border security and tackling illegal immigration.

Ms Harris is expected to highlight her work on the issue in her speech in Douglas on Friday afternoon, including drawing on her past work tackling international gangs of drug and people traffickers in California.

“As a former attorney general from a border state, she took on international gangs and criminal organisations who traffic drugs, guns, and human beings, and she has long believed we need an immigration system that is secure, fair, orderly and humane, a stark contrast from the divisive and dangerous politics of Donald Trump,” a Harris campaign aide said.

Ms Harris will also highlight her support for the tough bipartisan border security legislation that would have granted Mr Biden sweeping powers to shut down the border on days when crossings exceeded a certain threshold, toughen criteria for asylum claims and fund more border agents and deportation flights.

The legislation was blocked from advancing through Congress by Republican senators following a lobbying campaign by Trump who said he did not want to give Mr Biden a “win” on the border in an election year.

Ms Harris frequently highlights her opponent’s intervention to paint him as a political opportunist. “He killed a bill that would have actually been a solution, because he wants to run on a problem, instead of fixing a problem,” she told MSNBC in an interview this week.

While Trump has promised to carry out mass deportations and other measures to remove both illegal and legal migrants from the country, Ms Harris has attempted a more delicate juggling act.

She has supported tough action to secure the border against illegal immigration, while also backing a pathway to citizenship for some undocumented immigrants who came to the US as children.

Ms Harris has gained some ground among Hispanic voters, a significant voting bloc in Arizona, but Trump still holds a narrow lead in the state. It will be critical to winning the White House on Nov 5.