WASHINGTON — President Biden said Monday that he will visit the US-Mexico border Thursday — after former President Donald Trump arranged his own trip there on the same day to slam Biden’s policies.

Biden insisted to reporters that he didn’t know Trump would be at the border, but the 45th president claimed credit for forcing his successor and prospective 2024 rival to make the trip.

“I planned it for Thursday. What I didn’t know was that my good friend apparently is going,” Biden, 81, claimed as he got ice cream with NBC late-night host Seth Meyers next to 30 Rockefeller Plaza.

“Crooked Joe Biden has had three years to visit the border and fix the crisis he created,” Trump campaign press secretary Karoline Leavitt said earlier in the day. “Now Biden’s handlers are sending him there on the same day as President Trump’s publicly reported trip, not because they actually want to solve the problem, but because they know Biden is losing terribly.”

Leavitt added: “Biden’s last-minute, insincere attempt to chase President Trump to the border won’t cut it — Americans know Biden is single-handedly responsible for the worst immigration crisis in history and the ensuing Biden Migrant Crime Crisis affecting every community in our Country.”

Another Trump campaign official told The Post that Trump “will be delivering remarks at the border” and that “Biden chasing us to the border … shows just how big of a problem this is for him.”

Record-setting illegal immigration is one of the top issues in the likely election rematch between Biden and Trump, 77 — and their visits will follow the arrest Friday of illegal immigrant Jose Ibarra for allegedly killing Augusta University junior Laken Riley, 22, on the University of Georgia’s campus.

Venezuelan citizen Ibarra, 26, crossed the US-Mexico border illegally near El Paso in September before being released into the US.

Biden made the first known visit of his career to the border in January last year after sustained criticism from Republicans over his handling of the mounting illegal immigration crisis.

The latest trip comes as Democrats attempt to flip the political script by arguing that Republicans are to blame for the crisis after they blocked bipartisan legislation to grant Biden emergency powers to stem the flow of illegal immigrants — power that Republicans say he already has.

Biden “will travel to Brownsville, Texas, to meet with US Border Patrol agents, law enforcement, and local leaders,” a White House official said.

“He will discuss the urgent need to pass the Senate bipartisan border security agreement, the toughest and fairest set of reforms to secure the border in decades,” the official added.

“He will reiterate his calls for Congressional Republicans to stop playing politics and to provide the funding needed for additional U.S. Border Patrol agents, more asylum officers, fentanyl detection technology and more.”

Trump had planned to visit Eagle Pass, Texas, since last week, CNN reported at the time.

The former president similarly announced a visit to the border in June 2021 — shortly before Vice President Kamala Harris, whom Biden tapped to lead efforts to reduce illegal immigration, booked her own visit there. Trump also claimed credit for her hastily announced plans.

A Gallup poll last month found that immigration was the second-most common answer when Americans were asked to name the most important problem facing the US — with 20% naming that issue while 21% cited poor national leadership and 13% identified inflation and high costs of living.

Republicans blame the border crisis on Biden’s policies.

Biden halted construction of Trump’s US-Mexico border wall and scrapped Trump’s “Remain in Mexico” policy that required most asylum seekers claiming persecution in their homelands to await US court decisions on their status south of the border.

The migrant crisis has continued to grow throughout Biden’s three years in office.

December set an all-time monthly record with more than 302,000 people arrested for illegally entering the US from Mexico — equivalent to the populations of Pittsburgh or Newark.

Homeland Security Secretary Alejandro Mayorkas said in January that more than 85% of those detained for illegally crossing the border were being released into the US — up from 71% in October and 74% in November.

Asylum seekers are entitled to work permits after an initial 180-day wait period. A massive asylum processing backlog means that an actual adjudication of their claims could take nearly a decade.

A record of about 2.5 million people — nearly the population of Chicago — were apprehended after illegally crossing the US-Mexico border in fiscal year 2023, which ended Sept. 30, in addition to an estimated 670,000 “gotaways” who evaded authorities.

Fiscal 2022 set the previous record with nearly 2.4 million apprehensions along the border — up from 1.7 million in fiscal 2021, which Republicans at the time had deemed an urgent crisis.

The House of Representatives impeached Mayorkas on Feb. 13 for allegedly failing to enforce the country’s laws and for allegedly misrepresenting the degree of border security in congressional testimony. His Senate trial could begin as early as Wednesday.