Biden to extend US border wall with Mexico using Trump-era funds

US President Joe Biden has defended his plans to extend the border wall with Mexico, saying he didn't think such barriers worked, but he was bound by laws introduced under former president Donald Trump.

Biden, who is polling neck-and-neck with rival Trump ahead of a likely 2024 rematch, insisted on Thursday his predecessor had tied his hands on the wall-building.

"They have to use the money for what it was appropriated for. I can’t stop that," he told reporters in the Oval Office.

He said the cash was earmarked for the border wall by the US Congress under Trump in 2019, and that lawmakers had since rejected his appeals to reassign the funds.

Asked if he thought the border wall was effective, Biden replied simply: "No."

On Wednesday, the Biden administration waived 26 federal laws, allowing the construction of the wall.

Democrat Biden pledged during his White House race with Trump in 2020 that he would abandon the hard-right Republican's signature policy and would not build any more of the wall.

'Absolutely false'

Illegal immigration has become a major political headache for Biden, with opposition Republicans accusing him of lax border policies.

The border issue has even added to uncertainty over US aid for Ukraine, with some Republicans refusing to approve funds until Biden acts on refugees.

The new section of wall will be built in the "high illegal entry" Rio Grande Valley Sector of the US-Mexico border, where there have been more than 245,000 attempted illegal entries this fiscal year.

Homeland Security Secretary Alejandro Mayorkas said in a notice in the Federal Register that there was "an acute and immediate need to construct physical barriers and roads ... in order to prevent unlawful entries."

Mayorkas said the funding for the "additional physical barriers" would come from an appropriation made by Congress for that purpose in 2019, when Trump was still in office.

Officials said the money needed to be spent this year.

Some Democrats criticised Biden, who had announced in a proclamation on the day he took office in January 2021 that no more taxpayer funds would be allocated for a wall.

The White House said it was "absolutely false" that there had been a reversal by the president.

"We have to comply by law, and that's what we're doing," Press Secretary Karine Jean-Pierre told reporters.

Trump: I was right

Trump, the front runner for the 2024 Republican presidential nomination, said the Biden administration move showed "I was right when I built 560 miles [900 kilometres] ... of brand new, beautiful border wall."

"Will Joe Biden apologize to me and America for taking so long to get moving, and allowing our country to be flooded with 15 million illegals immigrants, from places unknown," Trump said on his Truth Social platform.

Mexican President Andres Manuel Lopez Obrador criticised the US plan, calling it a "setback" ahead of talks with visiting US Secretary of State Antony Blinken.

The meeting came after a spike in the number of people — mostly from Central America and Venezuela — seeking to cross from Mexico into the United States.