Colombian officials on Friday formally ended the search for survivors of floods in the country's southwest that killed at least 314 people, including 102 children - though 106 people still remain listed as missing.

Surging rivers triggered by torrential rains last week sent an avalanche of floodwaters, mud and debris through the town of Mocoa, causing widespread destruction.

"Without adverse conditions, a person can survive a long time, but with the quantity of mud and rocks in Mocoa, that is very difficult," said Manuel Infante, who has been leading volunteer firefighters who arrived from Cali.

"I'd say that the missing are dead," he added.

READ MORE: Bodies decomposing in Mocoa morgue after landslides

Emergency workers will turn to excavating roads and buildings, distributing aid and trying to avoid the outbreak of epidemics in the town, where water and power services remained cut a week after the avalanche of debris-filled water poured down from the mountains.

Defence Minister Luis Carlos Villegas said it "will take a generation" to completely restore the city.

Mocoa, the capital of the department of Putumayo, was home to 70,000 people, about 45,000 of whom were affected by the disaster, according to the Red Cross.

In an effort to speed up reconstruction, the government formally declared a 30-day state of economic, social and ecological emergency in Mocoa.



The measure will allow direct contracting of services without the need for formal, more time-consuming procedures.

Carlos Ivan Marquez, director general of the national anti-disaster agency, said emergency workers will begin using heavy equipment.

Officials late on Wednesday announced a probe to determine whether town authorities had correctly enforced building regulations and adequately planned for natural disasters.

Edgardo Maya, the national comptroller, said the investigation was "not about punishment; it's about prevention".

"What good does it do to punish people now, after so many deaths?" he said.



Mayor Jose Antonio Castro, regional governor Sorrel Aroca, and their predecessors face a separate investigation by prosecutors, according to Colombian media reports.

The hardest-hit areas were impoverished neighbourhoods populated by residents uprooted during Colombia's five-decade civil war.