Bogota: The death toll from a huge pipeline explosion in western Colombia last week has risen to 18, officials said after five people hurt in the blast succumbed to their injuries.

Some 100 were injured in the pre-dawn explosion Friday that ripped through a section of the pipeline near the city of Dosquebradas, creating an inferno that destroyed 35 shantytown homes and damaged 50 more.

Authorities initially blamed the blast on fuel thieves, but later backtracked to say the pipeline was likely fractured by unstable ground caused by heavy rains in recent weeks.

Most of Colombia is on alert over the intense downpours which have been blamed for at least 177 deaths since September and have left thousands homeless, according to the latest report from Risk Management.