Grieving parents prepared on Thursday to bury some of the 27 schoolchildren who died after eating cassava (search) — a root that's poisonous if not prepared properly — while 103 other people were hospitalized with severe stomach pain and diarrhea.

The victims, most aged 7-13, bought the deep-fried caramelized cassava from vendors during snack time at the San Jose ne island of Bohol.

One of the two vendors also fell ill and was still hospitalized Thursday, while the other was in police custody to protect her from outraged parents, said the town mayor's aide, Philip Fuderanan. Authorities have not ruled out criminal charges against the vendors.

Investigators were checking whether the vendors failed to properly cook the cassava, and studying unconfirmed reports that tainted cooking oil was used, said Health Secretary Manuel Dayrit.

President Gloria Macapagal Arroyo (search) said she was "deeply saddened" and traveled Thursday to Mabini, a small farming town, to console parents and declare an emergency so the province can use state funds to help victims' families.

"I pray to God that this will never happen again," Arroyo said in a statement. "I want the police to work with the health authorities to give me a detailed report on why and how this unfortunate incident happened."

Wailing parents left hospitals late Wednesday carrying their children's bodies wrapped in blankets. Mabini's Mayor Stephan Rances said a mass burial was planned for Thursday.

Before the funeral, men shouldered bamboo platforms with 12 coffins into a small, packed Roman Catholic chapel, where they were placed in a line before an altar in the sweltering heat.

Overcome with grief, Lorenza Asas, mother of 7-year-old Sherwin Asas, stomped her feet on the floor.

"I can't accept that my son is dead," she said, as her relatives tried to calm her.

Anicita Luyong, 33, grieved over the coffin of her 7-year-old son, Wilfredo Luyong Jr., in her house near the school.

She said her son, who wanted to be a soldier, came home crying with severe abdominal pain. He was taken to a hospital but did not survive.

"Our village is poor. Our rice farms are parched. We have no hope of a good harvest this season because there was no rain," she said. "The youth in the village are striving hard to study because we are poor."

Teacher Jennifer Hutuhot, 28, said the children had been playing happily during recess Wednesday.

"Coming back from recess into the room after 15 minutes, students began throwing up," she said. "Cheer turned into panic. The children were rushed to the hospitals, leaving their schoolbags behind."

"Some said they took only two bites because it tasted bitter," said Dr. Harold Gallego of Garcia Memorial Provincial Hospital in the town of Talibon, where 47 patients were taken.

Reuben Auditor, 13, said he did not eat a cassava snack offered by a classmate.

"I had chocolate," he said. "In our class two died. Our graduation will be sad."

The starchy roots of cassava, a major Southeast Asian crop, are rich in protein, minerals and vitamins A, B and C. However, it is poisonous without proper preparation. If eaten raw, the human digestive system converts part of it into cyanide.

The victims were taken to at least four hospitals near Mabini, about 610 kilometers (380 miles) southeast of Manila. Treatment was delayed because the nearest hospital was 30 kilometers (20 miles) away.

Dayrit said 27 students were confirmed dead. Most of the 103 people recovering in hospitals were children, and four were in critical condition, hospital workers said.

Those who had reached hospitals had a good chance of surviving, doctors said.

Officials of the National Bureau of Investigation and the Health Department were collecting cassava samples at the site and drawing patients' blood for analysis, said provincial health officer Reymoses Cabagnot.