Michael Hopkins, CEO of Jewish Family Service of San Diego, an agency that operates the shelter, said that since then, about 12,500 people have been released by the US and passed through the network's shelter, the only one in Southern California.

"These are families who crossed the border with no money, no cellphones and no tickets to go anywhere. They would more than likely be victims of human trafficking, or end up on the street if we didn't assist them," Hopkins said.

"San Diego has a large homeless population. Even if just a small percentage (of the 12,500 people released by the US) fell through the cracks, it would greatly increase the homeless population," he added.

Every day, US Immigration and Customs Enforcement officers drop asylum-seeking families at the shelter any time after 5 pm.

The facility currently shelters about 200 people, most of them staying for 24 to 48 hours before leaving for their final destinations across the US. California is their main choice, followed by Texas, Florida and New Jersey.

Staff members and volunteers at the shelter help to look after medical requirements, travel arrangements and legal work.

When migrants are dropped off at the shelter, they are thirsty and hungry, wearing clothes that have not been changed for months, and are without shoelaces (a jail suicide prevention policy), Hopkins said.

While they await medical screening, volunteers provide them with new clothing and shoes.

"We look for flu and tuberculosis symptoms, scabies and lice," Hopkins said. "We want to make sure that these folks are coming into the country healthy before they travel to their final destinations."

It is not unusual for families to cry when they eat dinner, as it is an emotional experience for both the migrants and those who work at the shelter, he said.

Although the shelter has secured $2.2 million in emergency funding from California to support operations through June, it still needs another $500,000 for the next six months.

On the Jewish Family Service of San Diego's GoFundMe page, nearly $196,000 has been raised in five months.

But anti-immigrant groups are protesting over what Hopkins considers critical humanitarian work.

"Haters have been here in front of the shelter when the bus drops off asylum-seeking families. They believe these people are invaders," he said. "All I see is young moms and dads with very young children who talk about making the journey because they want new lives for their children."

San Diegans for Secure Borders, one of more than 80 anti-immigrant groups in California listed by the Southern Poverty Law Center, has regularly posted memes mocking immigrants on its Facebook page.

One of the memes, a map of Mexico with "A" marked at the southern border with Guatemala and "B" at the northern border with the US, states, "If the migrants are escaping danger, why not seek asylum between A and B?"

It echoes the Trump administration's controversial policy Remain in Mexico, formally known as the Migrant Protection Protocols.