BOGOTA, Colombia (AP) — A multi-story tourist ferry packed with about 150 passengers for the holiday weekend capsized on a reservoir near the Colombian city of Medellin on Sunday. Police said three people were dead and 30 missing.

A major rescue effort involving Colombia's air force and firefighters from nearby cities was looking for survivors at the Guatape reservoir where the accident took place. Medellin's mayor appealed to motorists to stay off roads to facilitate the arrival of rescuers, ambulances and first responders.

"The most important thing right now is to save lives," said Mayor Federico Gutierrez.

Dramatic videos circulating on social media show the turquoise and yellow trimmed party boat, called El Almirante, rocking back and forth as people crawled down from a fourth-floor roof as it began sinking. A flotilla of recreational boats and jet skis rushed to the scene to pull people from the vessel and deliver them safely to the shore, avoiding an even deadlier tragedy.

Gen. Jorge Nieto, the head of Colombia's police, said three people had died and approximately 30 people were missing. Another 24 were being treated for injuries at a local hospital.

It's unclear what caused the boat to sink but survivors told local media that it appeared to be overloaded and none of the passengers on board were wearing life vests.

Daniel Giraldo, owner of an Italian restaurant in Guatape, said he went to the bay after hearing the sound of ambulances. When he got to the shore people told him the ship had gone under.

"It sank in a matter of four minutes," he said.

Next he went to the hospital where he said he saw a baby girl in a wet dress who had been saved but whose mother he was told is missing.

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 center hastily set up along the shore.

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 Sunday as Colombians celebrated a long holiday weekend.