At least six people were killed and 23 more were injured as a result of explosions at two shipyards in Cartagena, Colombia, VOA reported.

Colombian police are investigating the causes  of the explosions.

"There were three explosions, two of them at the same spot," a spokeswoman for the local fire service said. 

According to firefighters, an explosion struck  the premises of Colombian naval corporation Cotecmar, the other two  blasts rocked the Astivik Shipyards, owned by a U.S. corporation.

The shipyards in the Caribbean port's industrial zone are at least 15 km from Cartagena's center and tourist attractions including an old town section that has been declared a UNESCO World Heritage site.