MEXICO CITY, Feb. 21 (Xinhua) -- An explosion on Wednesday aboard a passenger ferry that was docked in Playa del Carmen, one of the Mexican Caribbean's top beach resorts, has wounded at least 18 people, the local government said.

"The reports we are getting is that people have sustained small cuts from splinters. Fortunately nothing serious, no life is in danger," Mayor Cristina Torres said in a statement.

Five of the injured were U.S. citizens and the rest Mexican nationals, the mayor's office added.

Video taken after the blast and posted online showed at least two ambulances on the dock attending to some of the injured.

Images of the ferry showed what appeared to be a two-meter-long portion of the vessel's second-floor exterior blown out, exposing splintered wood and metal.

Passengers were disembarking from the ferry, operated by Barcos Caribe, when the blast occurred around 1 p.m. local time.

Emergency services took 14 people to the hospital to be treated for their injuries, but no fatalities were reported, the mayor said, adding "tourists and residents ... at the beach close to the site of the accident are going about their activities normally."

The cause of the blast during peak tourism season has yet to be determined.

The ferry provides shuttle service between Playa del Carmen, located just 40 minutes south of Cancun, and the island of Cozumel. Passengers are mainly tourists or employees of hotels, restaurants and other businesses.