Authorities in Macedonia say five police officers have been arrested on suspicion of participating in a smuggling ring that allegedly helped hundreds of refugees and migrants cross the country's southern border with Greece.

Police said Wednesday that 14 other suspects were also arrested and an unspecified number of assault rifles and other weapons were seized following countrywide raids at 24 locations.

Macedonia closed its border in March amid efforts across Europe to prevent a repeat of mass migration to the continent in 2015. Thousands of stranded migrants remained camped out on the Greek side of the border until late May.