Coca-Cola's Spanish bottler's announcement that it will close four plants and lay off 750 workers set off a wave of protests, some of them violent, police said. Coca-Cola Iberian Partners has said it wants to consolidate its operations, ThinkSpain reported. The plants to be shuttered in about three weeks are in Madrid's Fuenlabrada district, Alicante, Palma de Mallorca and Colloto. In addition to the layoffs, 500 employees will be transferred from plants getting the ax. As demonstrators gathered Friday outside the Madrid plant, some threw Molotov cocktails at the building, National Police said. Investigators described the devices as plastic bottles containing an apparently explosive chemical and equipped with wicks. Police said no arrests were made, although investigators were trying to identify the bomb-throwers. The majority of demonstrators showed up and picketed without any violence or disturbance.