Heavy overnight rains into Monday prompted the Las Vacas river, which runs through Guatemala City, to burst its banks.
The worst damage was done to a shanty town a few kilometers from the capital, with corrugated iron buildings perched precariously in the river's valley, next to the freshwater source and underneath a major highway bridge passing far overhead.
"We've found six bodies for the moment, and we'll likely find more," said Sergio Cabanas, head of operations for the municipal fire department. "Among the bodies, there is a girl and five adults.
Guatemala's national disaster agency, Conred, said that the girl was thought to be between three and five years old.
At least 15 other people were believed missing. Initial comments from officials suggested 10 children were among those feared dead after the flood.
Firefighters and search and rescue dogs were combing the area trying to find survivors or signs of the missing people on Monday.
Images from the scene showed the path the landslide had crashed through, along with signs of domestic life strewn along the river bank.
When did the landslide strike?
The landslide struck around 2 a.m. local time (0800 GMT) and swept away six houses. The search operation was launched around three hours later.
Before Sunday's overnight rains, at least 29 people had been killed as a result of flooding in the rainy season in Guatemala.
Landslides are a constant threat in the mountainous country's rainy season, which runs until November.
There are few state controls on where people put their homes, particularly such poor settlements, putting the less wealthy at far greater risk.
According to World Bank simulations for 2019 — a proper estimate has not been conducted since 2014 — more than half of Guatemala's population of around 18 million lived below the poverty line, despite the country being considered an upper-middle income country overall. As well as being Central America's largest economy, it's also one of the more unequal.
Guatemala's municipal government announced that a shelter had been set up for those affected by the landslide with food and other support on hand.
msh/wmr (AFP, dpa, Reuters)