It was earlier reported that nine people drowned and 28 went missing after after the incident.
Colombia Air Force informed that the rescue operation was ongoing, as a boat carrying about 150 people, most of which were tourists, sank in a reservoir in northwest of the country.
The vessel reportedly went down in a reservoir for a hydro-electric dam in the Andean resort town of Guatape. According to El Pais newspaper, the shipwreck took place at 02:00 p.m. local time (19:00 GMT).
The Colombian authorities have launched a rescue operation, while the country's Air Force have sent helicopters to evacuate people.
Initial reports indicated that at least 25 people could have drowned in the incident.
COLOMBIA: VIDEO — A boat with 150 tourists on board has sunk in Colombia, leaving at least 25 dead and over 100 still missing. pic.twitter.com/UCBDRDrMDu— KolHaolam (@KolHaolam) 25 июня 2017 г.
BREAKING: Initial reports of at least 25 dead after a Boat carrying 150 tourists goes down in the Guatape reservoir, Colombia. pic.twitter.com/WxZW1vK2l5— News_Executive (@News_Executive) June 25, 2017