By HOLBROOK MOHR

A day after the largest single-workplace immigration raid in U.S. history, Elizabeth Alegria was too scared to send her son to school and worried about when she'd see her husband again.

Nearly 600 immigrants suspected of being in the country illegally were detained, creating panic among dozens of families in this small southern Mississippi town.

Alegria, 26, a Mexican immigrant, was working at the Howard Industries transformer plant Monday when U.S. Immigration and Customs Enforcement agents stormed in. When they found out she has two sons, ages 4 and 9, she was fitted with a bracelet and told to appear in federal court next month. But her husband, Andres, wasn't so lucky.

"I'm very traumatized because I don't know if they are going to let my husband go and when I will see him," Alegria said through a translator Tuesday as she returned to the Howard Industries parking lot to retrieve her sport utility vehicle.

The superintendent of the county school district said about half of approximately 160 Hispanic students were absent Tuesday.

Roberto Velez, pastor at Iglesia Cristiana Peniel, where an estimated 30 to 40 percent of the 200 parishioners were caught up in the raid, said parents were afraid immigration officials would take them.

"They didn't send their kids to school today," he said. "How scared is that?"

One worker caught in Monday's sweep at the plant said fellow workers applauded as immigrants were taken into custody. Federal officials said a tip from a union member prompted them to start investigating several years ago.

Fabiola Pena, 21, cradled her 2-year-old daughter as she described a chaotic scene at the plant as the raid began, followed by clapping.

"I was crying the whole time. I didn't know what to do," Pena said. "We didn't know what was happening because everyone started running. Some people thought it was a bomb but then we figured out it was immigration."

About 100 of the 595 detained workers were released for humanitarian reasons, many of them mothers who were fitted with electronic monitoring bracelets and allowed to go home to their children, officials said.

About 475 other workers were transferred to an ICE facility in Jena, La. Nine who were under 18 were transferred to the custody of the Office of Refugee Resettlement.

John Foxworth, an attorney representing some of the immigrants, said eight appeared in federal court in Hattiesburg on Tuesday because they face criminal charges for allegedly using false Social Security and residency identification.

He said the raid was traumatic for families.

"There was no communication, an immediate loss of any kind of news and a lack of understanding of what's happening to their loved ones," he said. "A complete and utter feeling of helplessness."

Those detained were from Brazil, El Salvador, Germany, Guatemala, Honduras, Mexico, Panama, and Peru, said Barbara Gonzalez, an ICE spokeswoman.

"We have kids without dads and pregnant mothers who got their husbands taken away," said Velez's son, Robert, youth pastor at the church. "It was like a horror story. They got handled like they were criminals."

Howard Industries is in Mississippi's Pine Belt region, known for commercial timber growth and chicken processing plants. The tech company produces dozens of products ranging from electrical transformers to medical supplies, according to its Web site.

Gonzalez said agents had executed search warrants at both the plant and the company headquarters in nearby Ellisville. She said no company executives had been detained, but this was an "ongoing investigation and yesterday's action was just the first part."

A woman at the Ellisville headquarters told The Associated Press on Tuesday that no one was available to answer questions.

In a statement to the Laurel Leader-Call newspaper, Howard Industries said the company "runs every check allowed to ascertain the immigration status of all applicants for its jobs."

Gov. Haley Barbour recently signed a law requiring Mississippi employers to use a U.S. Homeland Security system to check new workers' immigration status.

The law took effect July 1 for businesses with state contracts and takes effect Jan. 1 for other businesses. Mississippi lawmakers once used laptops made by Howard Industries, but it's not clear whether the company has current state contracts.

Under the law, a company found guilty of employing illegal immigrants could lose public contracts for three years and the right to do business in Mississippi for a year.

The law also makes it a felony for an illegal immigrant to accept a job in Mississippi. A message was left with the district attorney's office after hours seeking comment on whether he would use the law to bring state charges against Howard Industries or the workers.

The Mississippi raid is one of several nationwide in recent years.

On May 12, federal immigration officials swept into Agriprocessors, the nation's largest kosher meatpacking plant, in Iowa. Nearly 400 workers were detained and dozens of fraudulent permanent resident alien cards were seized from the plant's human resources department, according to court records. In December 2006, 1,297 were arrested at Swift meatpacking plants in Nebraska and five other states.