BOGOTA: Explosions at a shipyard in Colombia killed at least six people, including one on the premises of a US company, and injured 23 others on Wednesday, officials said. The blasts struck at the shipyard in the Caribbean port of Cartagena, where police were “investigating whether it was an accident or an attack,” a source in the force told AFP. “There were three explosions, two of them at the same spot,” a spokeswoman for the local fire service said. She said two of the blasts struck US shipbuilder Astivik. The third rocked the premises of Colombian naval corporation Cotecmar. Authorities did not immediately clarify how many died at each site. Firefighters put out blazes caused by the explosions, the spokeswoman told AFP. The shipyards lie in an industrial zone some 15 kilometers (nine miles) from the tourist center of Cartagena.