Updated June 26, 2017 11:28:15

Photo: Survivors said that it appeared to be overloaded and nobody on board was wearing a life vest. (AP: Luis Benavides)

A tourist boat packed with about 170 passengers for the holiday weekend capsized on a reservoir near the Colombian city of Medellin, leaving nine people dead and 28 missing, officials said.

Rescuers including firefighters from nearby cities and air force pilots were searching for survivors at the Guatape reservoir where the four-story El Almirante ferry sank.

A flotilla of recreational boats and jet skis rushed to the scene, pulling people from the boat as it went down and avoiding an even deadlier tragedy.

Dramatic videos circulating on social media show a multi-story ferry rocking back and forth as people crawled down from a third-floor roof as the ship began sinking.

"Those on the first and second floors sank immediately," a female survivor who was not identified by name told local TV station Teleantioquia.

"The boat was sinking and all we could do was scream and call for help."

Margarita Moncada, the head of the disaster response agency in Antioquia state, said that according to a preliminary report 99 people were rescued and another 40 managed to find a way to shore on their own and were in good condition.

Speaking to reporters from the reservoir, she said nine people had been killed and about 28 were still missing.

It is unclear what caused the boat to sink, but survivors said that it appeared to be overloaded and nobody on board was wearing a life vest.

Survivors told local media that the boat, called El Almirante, appeared to be overloaded and none of the passengers on board were wearing life vests.

Photo: Social media video captured the moment the boat sank as emergency services responded. (Twitter: Mapache con Gafas)

Authorities were at a loss to say exactly how many people were on the boat and asked passengers or their loved ones to report to a rescue centre hastily set up along the shore.

They also made a call for scuba divers to assist with the search.

The reservoir surrounding the soaring rocky outcrop of El Penol is a popular weekend destination a little more than an hour from Medellin.

It was especially busy on Sunday as Colombians celebrated a long holiday weekend.

Photo: The Guatapé reservoir is a popular destination in the town, which is known for its brightly coloured houses and streets. (Flick: JoseDGl, C.C. 2.0)

AP

Topics: disasters-and-accidents, maritime, colombia

First posted June 26, 2017 08:54:32