WASHINGTON, Oct 5 (AFP) - The Biden administration quietly announced plans on Thursday to add to the border wall with Mexico – extending construction of the barrier that was a signature policy of Donald Trump.

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

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

Joe Biden pledged while running for the White House he would not build any more border wall, and announced in a proclamation on the day he took office in January 2021 that no more taxpayer funds would be allocated to do so.

"Building a massive wall that spans the entire southern border is not a serious policy solution," Biden said in a proclamation that also terminated Trump's declaration of a "national emergency" at the southern border.

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.

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

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

"Will Joe Biden appolgize (sic) 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.

Republican Senator Marsha Blackburn said on X, formerly known as Twitter, that Biden had vowed during his presidential campaign he would "never build 'another foot of wall' along the southern border."

"Now, Biden is fast-tracking the construction of approximately 20 miles of new wall," Blackburn said. "Joe finally realized walls work."