President Joe Biden is under fire from both sides of the political spectrum after his administration announced new border wall construction in Texas.
Mr Biden has said he “can’t stop” the work because the funding was signed off while Donald Trump was president.
Members of Mr Biden’s Democratic Party said walls did not work, while rival Republicans accused him of hypocrisy.
The Department of Homeland Security has said there is an “acute” need for the barriers.
US authorities have detained over 2.2 million migrants this fiscal year alone.
The growing number of migrants in US cities such as New York have increasingly become a challenge for Mr Biden, who has faced intense criticism over his handling of the border.
According to US officials and President Biden, funding for the new border barrier – first announced in late June – was appropriated during the 2019 fiscal year, under Mr Trump’s presidency.
Approximately 20 miles (32km) of new border barriers will be built in Starr County, a sparsely populated stretch of border in the Rio Grande Valley.
In 2020, Mr Biden promised he would not build another foot of wall if elected.
The Texas town caught in America’s border battle
A senior administration official on Thursday laid the blame for the new construction on the US Congress, claiming it resisted efforts to “rescind” the funds in Mr Biden’s first budget request issued in May 2021.
Under a 1974 law, appropriated funds must be made available for their intended purpose unless a rescission is approved by both the Senate and House of Representatives.
“We have repeatedly asked Congress to rescind this money but it has not done so and we are compelled to follow the law,” Homeland Security secretary Alejandro Mayorkas said in a statement.
Mr Biden and the statements stand in stark contrast to a notice about the project on the US Federal Registry.
In that, Mr Mayorkas said there is “presently 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 into the United States in the project areas”.