US President Joe Biden on Wednesday tasked Vice President Kamala Harris with tackling an influx of migrants on the Mexican border, aiming to take charge of a situation that has energized opponents of the new administration.

"I can think of nobody who is better qualified to do this," Biden said at a White House meeting with Harris and other top officials as thousands flee violence in impoverished Central America.

"When she speaks, she speaks for me," Biden said, adding: "I give you a tough job."

Migrants crowd a temporary processing center in Donna, Texas
Migrants crowd a temporary processing center in Donna, Texas US Customs and Border Protection / Jaime RODRIGUEZ Sr.

Harris said there was "no question that this is a challenging situation."

It marks the first time that Biden has assigned a specific portfolio to Harris, who is seen as representing a younger generation in the Democratic Party and has been constantly at his side since they entered office on January 20.

The administration also announced that the San Diego Convention Center would become the latest shelter for the rising number of migrant children and it sent a team to tour an existing facility in Texas.

A migrant girl from Central America waits with her mother for a bus after they are dropped off by the US Customs and Border Protection near the Gateway International Bridge between Brownsville, Texas, and Matamoros, Mexico, on March 15, 2021
A migrant girl from Central America waits with her mother for a bus after they are dropped off by the US Customs and Border Protection near the Gateway International Bridge between Brownsville, Texas, and Matamoros, Mexico, on March 15, 2021 AFP / CHANDAN KHANNA

The convention center will accommodate up to 1,400 children, said a spokesperson for the Office of Refugee Resettlement.

In a sign of shifting national focus, the San Diego center until recently had been repurposed for the Covid-19 pandemic as a homeless shelter that permits social distancing between beds.

Speaking earlier to CBS News, Harris acknowledged that the United States needed to speed up its processing of migrants' asylum claims and care better for them.

"It's a huge problem. I'm not going to pretend it's not," Harris said in the interview.

US Vice President Kamala Harris, speaking before a virtual bilateral summit with Ireland on March 17, 2021, has called the situation on the Mexican border a "huge problem."
US Vice President Kamala Harris, speaking before a virtual bilateral summit with Ireland on March 17, 2021, has called the situation on the Mexican border a "huge problem." AFP / MANDEL NGAN

But she said that the administration, in office for less than 100 days, needed to repair a structure torn apart by former president Donald Trump, who rose to power on an aggressive anti-immigration agenda.

"We have to reconstruct it. It's not going to happen overnight," Harris said of the immigration system.

She also vowed a greater effort to address the "root causes" of the border situation -- helping the so-called Northern Triangle of Guatemala, Honduras and Nicaragua so its people do not feel they need to flee.

The Washington Post, in an analysis looking at data, said there in fact has been no "surge" of migrants entering the United States, with recent numbers in line with seasonal norms before the pandemic.

But more of the migrants are children, officials say, and the border influx has provided Republicans a line of attack against Biden, who in his first weeks has succeeded in his promises to ramp up Covid vaccinations and to push through an economic package that offers relief to most Americans.

Republicans accuse Biden of encouraging migration through a more welcoming approach than Trump, who in his final year essentially closed the border to all undocumented migrants by citing a public health emergency from Covid-19.

Top House Republican Kevin McCarthy has spoken of a "Biden border crisis" and former secretary of state Mike Pompeo tweeted that Biden "supports restrictions on pretty much everything except the border."

Biden halted construction on Trump's cherished wall on the Mexican border and has moved to wind down a controversial Trump policy, which migrant advocates say violates international conventions, in which asylum seekers are forced to wait in Mexico while their cases are heard.

Biden has also faced concern from fellow Democrats who are alarmed at the conditions for children.

In one of Trump's most draconian actions which his aides saw as a deterrent, the United States separated thousands of Central American children from their parents.

While the Biden administration is still expelling adults who arrive without documentation, it has refused to send back into harm's way children who are unaccompanied by a guardian.

Secretary of Homeland Security Alejandro Mayorkas has acknowledged that the United States is falling short in its goal of transferring all children out of custody of border forces within 72 hours.

Some critics accuse Biden of replacing Trump's unapologetically harsh measures with an approach of hiding the treatment of migrants by restricting media access.

The White House said it was committed to transparency and would work to let in more journalists on the ground.

One television network was granted access to pool coverage of Wednesday's tour by White House officials and lawmakers of the center in Carrizo Springs, Texas.

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