The burial chamber is the oldest uncovered in the Mayan city of Waka, 40 miles from the Tikal ruins.
Nine children were flown to hospitals in Boston, Cincinnati and Galveston, Texas.
The former TV comedian who has never held office claimed victory after milking public anger over a corruption scandal.
Distraught relatives of the victims shoveled alongside diggers through the mounds of earth.
Emergency services call it one of the worst mudslides to hit the impoverished Central American country in recent memory.
The charges against Perez include illicit association, taking bribes and customs fraud.
In Guatemala, dissenting villagers face violent attacks, arson and intimidation from supporters of a burgeoning mining industry