March 12 (UPI) -- The death toll from the fire at Guatemala's Virgen de la Asunción shelter for girls in the municipality of San José Pinula has risen to 40, officials said.
Four of the girls hospitalized after the fire on Wednesday were flown on an airplane ambulance to the United States for treatment at the Shriners Hospital for Children of Galveston, Texas, Saturday night.
The 40th victim died early Sunday in Guatemala City's Hospital Roosevelt. The hospital said that out of 22 girls admitted to the hospital, 10 have died, five have been discharged, four are in stable condition and two are in critical condition. One of the girls at that hospital was among those taken to the United States.
Guatemala's Ministry of Health said at several girls are in critical condition at the San Juan de Dios General Hospital, which is closer to the state-run Virgen de la Asunción Safe Shelter where the fire occurred.
Guatemala's National Institute of Forensic Sciences said the cause of death for most victims -- mostly aged from 14 to 17 -- was suffocation by carbon monoxide poisoning. Some girls were badly burned.
The cause of the fire is under investigation. Witnesses said the fire may have started after mattresses were intentionally set ablaze in a bedroom, which caused the fire to spread rapidly. Some Guatemalan human rights officials accused officials of locking girls in that room with no chance of escape.
On Tuesday, police intervened in a riot at the shelter that takes in children up to the age of 18 who have been abandoned or are the victims of abuse or trafficking. Judges have also sent teenagers involved in criminal cases to the shelter, making it serve as a juvenile detention center.
Witnesses said the riot and subsequent fire occurred as a protest because of the poor conditions in the shelter.
Guatemalans on Saturday protested outside of Guatemala City's National Palace demanding justice for victims and the resignation of Guatemalan President Jimmy Morales.
"This tragedy marks the need for national unity," Morales said in an address after the incident.