Four car bombs exploded in Ecuador overnight within hours of each other without injuring anyone, police said Thursday, but they served to underscore the South American country’s fragile security. Ecuador’s National Police said two of the bombs exploded in Quito, the capital, while the other two went off in a province that borders Peru. Ecuador National Police Gen. Pablo Ramírez, the national director of anti-drug investigations, told reporters Thursday the explosions in Quito were related to “several transfers of inmates” that took place this week.