At least nine dead as tourist boat capsizes in Colombia

At least nine people have died after a tourist boat carrying 160 people capsized in Colombia.

A total of 15 people are still missing after the boat sank on a reservoir near the city of Medellin.

Scuba divers are carrying out searches for bodies in the reservoir where the vessel went down.

Dramatic videos on social media show the party boat rocking back and forth as people crawled down from the roof as it sank in a matter of minutes.

People cry as they wait for news of loved ones. Credit: AP

Survivors described hearing a loud explosion near the men's toilet that knocked out power a few minutes after the boat began its cruise around the giant lake.

As water flooded on board, pressure built and people were sucked under by the sinking ship.

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

Passengers were sucked under as the boat sank. Credit: AP

"Those on the first and second floors sank immediately," survivor Lorena Salazar told local media. "All we could do was scream and call for help... it was completely chaotic."

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 reached shore on their own.

Of the 134 people who survived the crash, three remain in hospital but are out of danger, said Margarita Moncada,the head of the disaster relief agency in Antioquia state.

It is unclear what caused the boat to sink.

Some people who witnessed the tragedy from the shore said the boat appeared to be overloaded but Mr Santos said it was sailing well below capacity.

None of the passengers were wearing life vests. Complicating the search, there was no passenger list.