Brownsville, Texas - President Joe Biden and Donald Trump will both visit the US-Mexico border on Thursday in a high-profile clash of schedules as they vie to win over voters on immigration – one of the hottest issues in the 2024 election.

With record numbers of migrants crossing into the United States, Biden has sought to defuse a major threat to his reelection campaign by blaming Congress for failing to back his reforms.

For Trump, a hard anti-immigration stance has been central to his political identity for years, and he has repeatedly vowed to crack down on crossings from Mexico as he seeks a return to the White House.

The rivals are set to visit different parts of the border in Texas on Thursday, setting up a notable split-screen moment less than eight months before Americans go to the polls.

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White House spokeswoman Karine Jean-Pierre declined to comment after Trump officials claimed without evidence that Biden had hurriedly planned his trip after Trump's visit was announced.

"I don't have a reaction to the former president; I am not going to speak to his schedule," Jean-Pierre said, adding that Biden would meet with border patrol agents, law enforcement, and local leaders in Brownsville, Texas.

"He will reiterate his calls for congressional Republicans to stop playing politics and to provide the funding needed for additional US Border Patrol agents, more asylum officers, fentanyl detection technology and more," she said.

Jean-Pierre also declined to confirm if the president would meet with migrants after criticism that he did not do so on a previous visit.

Trump, who will head to Eagle Pass, about 300 miles to the west of Brownsville, unleashed a fresh social media outburst over migration.

"Vicious gangs and gang members are pouring into our country from South America, and from all over the world... deposited into the Good Ole' USA by the tens of thousands," Trump said.

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"Biden will never be able to handle it."

A Trump spokesman said, "Biden chasing us to the border on the same day shows just how big of a problem this is for him."

Republicans blame Biden's policies favoring the right to asylum for migrants, while the White House says that Trump's party is deliberately sabotaging a bipartisan attempt to find a solution.

The latest bill, which has stalled in the Senate after the Republican leadership in the House of Representatives pledged to torpedo it, would be "the toughest and fairest set of reforms to secure the border in decades," Jean-Pierre told reporters aboard Air Force One as Biden headed to New York for a campaign event, despite including some of the most severe attacks on immigration in decades.