ZAMORA, Mexico (AFP) - Parents of some of the 458 children rescued from a squalid shelter in western Mexico told horror stories on Wednesday after authorities raided it over alleged sexual assaults and other abuses.

Seeking to get their children back, families from around the country gathered at the charitable shelter, "La Gran Familia" (The Big Family), where the children were still being kept under authorities' care after police arrested the facility's director, Rosa del Carmen Verduzco, and eight employees. Lucia Carranza said she was anxious to see her five-year-old son after only being allowed three visits a year since handing him over to the shelter.

"My husband and I were day workers, we worked in the countryside and survived by the grace of God, so I couldn't keep my baby and they recommended this place," Mrs Carranza, 25, said. "I thought I would be able to see him every week like at other facilities, but no.... We looked for lawyers but everyone told me it was impossible to do anything against her (Verduzco)."

Police found 596 people, including 138 adults, living amid rats and insects when they raided the home on Tuesday after complaints of abuse and kidnapping.

Early investigations indicate Verduzco and her staff inflicted "a variety of physical and psychological abuse" on the residents, said Tomas Zeron de Lucio, an investigator at the attorney general's office.

The children were forced to beg in the street, sleep on the floor and eat unfit food, he told journalists. Some residents were also sexually abused, he said.

The rescued children included six babies, who officials said had been born at the home and registered as the director's own. One former resident, Ms Bertha Saucedo, told Foro TV that Verduzco had forced her to give up her daughter, who has Down's syndrome, after she gave birth at the shelter.

"They took my daughter away from me when she was three months old. When she was six years old, I started coming to see her and she (Verduzco) never let me see her because she had Down's syndrome and if I didn't pay her she was never going to give her back," she said. "I didn't file a complaint because I was afraid they would treat her badly, hit her and take her food away."

Authorities did not explain how the adults at the facility had been held against their will.

La Gran Familia was founded in 1947, according to its Facebook page, and houses residents ranging from newborns to adults over the age of 40. Locals described Verduzco as a respected, and sometimes feared, figure in Zamora, a town of 186,000 people about a 90-minute drive from Morelia, the capital of Michoacan state.

The shelter was a regular stop on the campaign trail for local and state politicians in Michoacan, a rural state plagued by drug trafficking. Some family members said Verduzco's political influence had deterred them from fighting to get their children back.

"At the Michoacan prosecutor's office, they just told me it was impossible to do anything against that lady," said Avigail Martinez, who had come to bring home her son.

A prominent Mexican writer and historian, Enrique Krauze, spoke out in Verduzco's defence after the raid, praising her "life dedicated to taking in orphans" and vowing an international protest.

The shelter's Facebook page shows Verduzco with former president Felipe Calderon and a former Michoacan governor, along with colourful images of children playing musical instruments, marching in a parade and riding on a toy train.

According to the website, the director has personally adopted all the children - "that is to say, all the children have the last name 'Verduzco,'" it says. "Inside this home Mama Rosa - or the 'Boss,' as everyone in Zamora calls her - provides them education... as well as different activities such as art, fashion workshops, metalworking, bricklaying and music."