Immigration authorities released hundreds of undocumented workers apprehended during a series of high-profile raids at seven workplaces in Mississippi — but immigrant communities in the area are still reeling from the massive operation.

In what officials touted as the largest single-state immigration enforcement sweep in U.S. history, Immigration and Customs Enforcement (ICE) agents rounded up nearly 700 undocumented immigrants at seven food processing plants in Mississippi on Wednesday. By Thursday afternoon, authorities had released nearly 300 of the workers, mostly on "humanitarian grounds."

But Amelia McGowan, an attorney for the Mississippi Center for Justice, said the large-scale operation will still have lasting effects on many families.

Get Breaking News Delivered to Your Inbox

"Everybody is in removal proceedings now. They are facing that process and we're trying to get them legal help," McGowan told CBS News, noting that all apprehended workers are served with notices to appear in court, regardless of whether they are released. "But they are living in constant fear that this can happen again."

Friends and family console each other while U.S. immigration officials raided Koch Foods Inc., plant in Morton, Miss., Wednesday, Aug. 7, 2019. U.S. immigration officials raided several Mississippi food processing plants on Wednesday and signaled that the early-morning strikes were part of a large-scale operation targeting owners as well as employees. AP

Those who weren't released — approximately 400 immigrants — will be moved to ICE detention facilities in Mississippi and Louisiana.

McGowan is the sole immigration lawyer in her organization, one of the few groups in predominantly rural Mississippi that offer pro-bono legal assistance to migrants and immigrants. Before the massive operation, she was representing four migrants from Guatemala: Two mothers, a 19-year-old woman and one man. All were apprehended during the raids.

As of Thursday afternoon, McGowan has only heard from two of her clients, and had been trying to contact family members of the two mothers.

Although it does not have as large of an immigrant and Latino community as states like New York and California, McGowan said Mississippi has seen an increase in residents from Central America, particularly indigenous people from Guatemala, who come to work in the local food processing plants.

She said Wednesday's raids will cause irreparable harm to this growing community, while leaving the companies who employed the workers mostly off the hook.

"It's the communities that are really destroyed after this. And I think it's to cause terror and fear — just fear of living your daily life," she added. "It tore apart these communities, regardless of your immigration status."

Officials framed the operation as a crackdown on employers who hire undocumented workers. But advocates have long denounced the disparity between the prosecution of unauthorized immigrants and the people who employ them.

Researchers at Syracuse University in New York found that between April 2018 and March of this year, just 11 individuals were criminally prosecuted for knowingly hiring unauthorized workers, and only three of them were sentenced to time in prison. No companies were prosecuted. During that same time span, more than 85,000 immigrants were prosecuted for illegal entry.

Handcuffed female workers are escorted into a bus for transportation to a processing center following a raid by U.S. immigration officials at a Koch Foods Inc., plant in Morton, Miss., Wednesday, Aug. 7, 2019. U.S. immigration officials raided several Mississippi food processing plants on Wednesday and signaled that the early-morning strikes were part of a large-scale operation targeting owners as well as employees. AP

Officials on Thursday said that all those detained on Wednesday were asked if they had any children at school or childcare. They said ICE agents released single parents with minor children, as well as one of two parents of minor children if they apprehended couples. Agents allowed migrants to make calls to ensure their children were being taken care of and worked with school districts during the operation.

During a call with reporters Thursday afternoon, ICE officials said they encountered 18 minors working at the sites, the youngest being 14.

CBS News pressed the officials on whether they could say for sure that none of the nearly 400 people still in custody are single parents with no one to take care of their children.

Officials said they took "a lot of steps" to ensure the apprehended workers could connect with their children.

"But to be able to tell you absolutely that there's no one in custody that's a single parent with no one to take care of their child, I don't think I can say that," one official said.