MEXICO CITY -- An explosion ripped through a ferry as it unloaded passengers in the Caribbean beach city of Playa del Carmen on Wednesday, hurting as many as 25 people, but authorities said none of the injuries were life-threatening.

Initial reports on the number of victims varied. The local municipal government and the port authority both reported that 18 were injured, including 15 Mexicans and three Canadians. Local Civil Defence director Juan Medina Sosa said there were 25 injured, including three Canadians and two Americans, and all were in good condition.

The U.S. Embassy in Mexico said in the evening that it was aware of seven Americans hurt in the incident, while Canada's diplomatic mission said it had not received any information that any of its citizens were harmed.

The municipal government said in a statement that the victims sustained minor cuts and were taken to a hospital for treatment.

Videos posted online by the newspaper Quintana Roo Hoy showed the blast sending a fireball and debris flying sideways from the ferry as it was moored to the dock with people nearby.

The Barcos Caribe vessel was left with a gaping hole in its starboard side next to a passenger seating area.

The municipal statement said the explosion happened when passengers were getting off the boat, and the cause was not yet known.

The Port Administration of Quintana Roo state said in a statement that preliminary indications suggest a mechanical failure may have been to blame.

It added that service to the nearby resort island of Cozumel would continue with other ferry companies that operate from the municipal dock.