Sources told DailyMail.com that 12 buses containing 725 children arrived on just one night shortly after the temporary facility opened in April.
The facility has space for 1,450 children and is already nearing capacity with 1,317 installed at the center on May 1.
It comes as Texas has been overwhelmed by an influx of migrants crossing the Rio Grande River – many of them families and unaccompanied children.
On Monday the White House released new data claiming that the number of migrant minors in US Customs and Border Protection custody has dropped by 88 per cent from the end of March.
According to the figures touted by DHS Secretary Alejandro Mayorkas, only 677 children remain in CBP facilities, down from the 5,767 on March 28.
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Hundreds of unaccompanied migrant children are being flown in to San Diego shelters after crossing the border in Texas. Pictured: A group of girls waiting in line outside the San Diego Convention Center
Exclusive DailyMail.com photos lay bare the bleak reality of the temporary shelter, with girls pictured being walked through a loading dock at the back of the center to use the showers
The San Diego Convention Center has been transformed into an ’emergency intake site’ for migrant children as US border officials struggle to cope with the influx of asylum seekers at the border
CBP has been able to almost double the rate it processes children and more quickly transfer them to shelters and emergency housing facilities set up by Heath and Human Services.
But despite the expediting processing, the number of illegal crossings have not slowed.
The most recent figures show that illegal crossings shot up by 70 per cent between February and March, with Border Patrol saying they encountered 101,028 people in February and 172,331 the following month.
Texas is the busiest state and has asked the Federal Government to step in with help – with HHS Secretary Xavier Becerra asking other states to take a share of the children.
But with California also dealing with record numbers, authorities have had to create emergency shelters such as the conference center facility.
Carol Fiertz, of the US Department of Health and Human Services which is running the shelter, said: ‘Our facility was originally intended to care for females between 13 and 17.
‘Then the decision was made to include younger siblings. We are now organized to care for both boys and girls ages five to 12 and females aged 13 to 17.
‘Most children are from Guatemala, Honduras, and El Salvador with smaller numbers from other countries.
‘Our goal is to place all of the children in our care with their US sponsors before we relinquish the site back to the Convention Center on July 15th.’
Most of the deportees are flown in from Brownsville, Texas, where the majority of migrants cross into the US
DailyMail.com witnessed the ICE chartered flights arriving, with migrants unloaded from the plane and loaded onto three buses on every occasion
The children (pictured after being loaded onto buses) are then transported to the shelters, which are being run by local charities and the US Department of Health and Human Services
Sources told DailyMail.com that 12 buses containing 725 children arrived on just one night shortly after the temporary facility opened in April. It was initially intended to house only females ages 13 to 17, but officials are now also taking in boys and girls ages five to 12
One of the buses is sent north to the shelters, while the other two head south to the border accompanied by a Border Patrol car
Access to the facility is tightly controlled, with authorities drawing curtains around the huge venue to protect the children’s privacy while cops patrol the area, including with sniffer dogs.
But charity workers are allowed in, with Nadine Toppozada, director of refugee and immigrant services at Catholic Charities San Diego, among them.
The NGO is scheduled to begin providing legal services to the children in May and Toppozada visited shortly after the first busloads of girls arrived.
She described a spartan setting with the children sleeping on camp beds in pods of 20, each with their own monitor.
Toppozada said: ‘It’s an emergency intake site [EIS] so the girls have beds plus health screening and access to medical care.
‘Each bus that arrives stays together as a group and they sleep in their own curtained off sections and eat meals together with their monitor.
‘They’re given new clothes and there are activities for them to do – there’s a soccer field for them – but minimal educational facilities because it’s a temporary site.’
Once they arrive, the migrant girls are grouped together, assigned a monitor and are given new clothes, health screenings, and a camp bed
Access to the facility is tightly controlled and monitored by police officers with sniffer dogs
Authorities have also drawn curtains around the huge venue to protect the children’s privacy. Pictured: Security guards at the San Diego Convention Center
She added: ‘There’s two monitors to every 14 girls and they accompany them to the showers and the restroom, as well as chaperoning them.
‘They help them make calls to their families and act like big sisters to them – they’re all in their early 20s so close in age to the older girls.
‘Some of the girls are pregnant so they take them to health screenings.’
Exclusive DailyMail.com photos lay bare the bleak reality of the temporary shelter, with girls pictured being walked through a loading dock at the back of the center to use the showers.
The same girls were later seen being handed bedding packs, including pillows and a basic duvet.
‘All children at the San Diego Emergency Intake Site receive breakfast, lunch and dinner, three snacks, recreation, showers, phone calls to family or sponsor, COVID-testing, vaccinations for MMR and varicella, case management by appointment, educational programming, and Know Your Rights presentations and legal aid,’ Fiertz said.
Toppozada says the shelter is ‘beautifully run’ and is keeping the girls safe until they can be returned to their families or united with sponsors in the US.
The temporary shelter is one of a network operated in California – which currently includes two hotels in El Centro, the Travelodge and Ramada
Vino Panajor, CEO of Catholic Charities San Diego (pictured) told DailyMail.com at least 40 per cent of migrants who cross over in to the US stay, and ‘at that point, they’re no longer undocumented migrants because they have papers’
But she says the real challenge comes once they turn 18.
‘Once they turn 18, they’re no longer a minor and they’re treated the same as single adults.
‘We call it the “rocket docket.” They have credible fear interviews with an ICE asylum officer and after that, they go to court to have their case heard. If it’s denied, they get deported immediately.’
The temporary shelter is one of a network operated in California – a number that currently includes two hotels in El Centro and several apartments in San Diego.
Families arriving in the San Diego sector are cared for by Jewish Family Services and Catholic Charities San Diego, but single men and women are expelled – frequently via San Diego’s San Ysidro border crossing.
Nadine Toppozada, director of refugee and immigrant services at Catholic Charities San Diego, said the shelter aims to keep migrant girls safe until they can be returned to their families or united with sponsors in the US
Due to the crisis, deportation flights have been stepped up with one or two arriving in the city each day.
Most of the deportees are flown in from Brownsville, Texas, where the majority of migrants cross into the US.
DailyMail.com witnessed the ICE chartered flights arriving, with migrants unloaded from the plane and loaded onto three buses on every occasion.
One of the buses is sent north to the shelters, while the other two head south to the border accompanied by a Border Patrol car.
An airport worker told DailyMail.com: ‘We’re getting at least one of these flights a day now, sometimes two.
‘You can’t go over to them – the cops will stop you.’
Vino Panajor, CEO of Catholic Charities San Diego, said: ‘At least 60 per cent of the people who come are deported straight away.
’40 per cent stay and at that point, they’re no longer undocumented migrants because they have papers.
‘We help them go through the asylum process and make sure they have clothing, shelter and all their basic needs.’
Meanwhile, the migrants that are expelled at the border – most of whom are single men and women – have been forced to seek help from charities in Tijuana that are now also overwhelmed
Migrant charity Border Angels says many would-be asylum seekers are now having to sleep in tent cities in the El Chaparral district close to the border wall
For those who are expelled, there’s little help to be had once in Mexico.
Dulce Garcia, of migrant charity Border Angels, said their 16 Tijuana shelters are overwhelmed.
As a result, many of the would-be asylum seekers are forced to sleep in tent cities in the El Chaparral district close to the border wall.
Photos obtained by DailyMail.com show the chaos, with hundreds of people seen lining up for food handouts in filthy conditions.
Garcia said: ‘We are supporting the 16 shelters that are housing migrants and the encampment at el Chaparral where hundreds of migrant kids are sleeping in the streets in tents.
‘The border crisis is really a humanitarian crisis in which migrants are denied their right to claim asylum because the border remains closed. This has caused so much chaos in our border.’