Despite a dramatic influx of immigrants, President Joe Biden’s administration on Wednesday assured Congress that the US border with Mexico is “secure”.

Amid mounting criticism over an immigration surge, Homeland Security Secretary Alejandro Mayorkas said, “The border is secure, and the border is not open,” once again defending the government’s policies in the face of “historic and unprecedented challenges” involving undocumented immigration. 

“The situation is undoubtedly difficult,” Mayorkas told the House Homeland Security Committee in his first hearing since assuming his post in February, AFP reported.

“We are working around the clock to manage it, and it will take time,” he said. “But we will not waiver in our commitment to succeed.”

Mayorkas also said that migrants including adults travelling alone and families travelling together are being “immediately expelled” if they are apprehended near the border, under public health guidelines aimed at preventing the spread of the coronavirus.

One day earlier Mayorkas said the United States was on track to encounter more migrants at the border than at any time in the past two decades — including thousands of unaccompanied children — but said such spikes were not new, having also occurred in 2019, 2014 and earlier.

But the crisis has swelled in the opening months of Biden’s term with Republicans saying his policies are failing to slow the tide, prompting the new president to address the issue Tuesday.

“I can say quite clearly, don’t come over…. Don’t leave your town or city or community,” he said in an interview with ABC News, addressing the migrants.

The homeland security panel’s chairman, House Democrat Bennie Thompson, stressed that authorities now are expelling more migrants than during the Donald Trump administration, and applauded Mayorkas and Biden for reversing policies including mandating those asylum seekers remain in Mexico while their cases are processed.

“What we must not do is return to the morally bankrupt politics of the last administration,” Thompson said, as he also slammed critics for “fearmongering about the challenges we face at the border.”

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But Republicans launched fiery criticism at Mayorkas, saying it was Biden’s less aggressive approach to tackling immigration that has fueled the crisis.

“Cartels and traffickers see that the green light is on at our southern border, and the United States is open for business,” congressman Michael McCaul told Mayorkas.

On January 20, his first day in office, Biden scrapped several of Trump’s contentious immigration policies, including halting new construction of a border wall and proposing legislation to create a citizenship pathway for the nearly 11 million undocumented people in the United States.