HOUSTON, June 7 (Xinhua) -- Six children who have been burned by the volcanic eruption in Guatemala on Thursday arrived in Houston in the U.S. state of Texas for medical treatment.

At a press conference held in Galveston County, about 80 km southeast of downtown Houston, doctors from Shriners Hospital said that the children sustained burns from ash clouds.

Each patient is described as having "massive burns" on more than 15 percent of their body surface and the healing process would take years.

According to the doctors, the treatment is free of charge and when the children and their families are able to return home to Guatemala, the doctors will fly with them to check in.

Death toll from the eruption of the Fuego volcano in Guatemala has risen to 99 as more bodies were found on Wednesday.

Fuego volcano, located about 50 km west of the capital of Guatemala City, exploded on Sunday. According to a preliminary report from the National Coordination for Disaster Reduction of Guatemala (CONRED), the eruption is "the strongest one recorded in recent years."

According to volcanologists, eruption records for Fuego Volcano, one of the country's most active volcanoes, date back to 1542. At its fiercest, the volcano could spray ash all the way to Guatemala's southern neighbors of El Salvador and Honduras.