Officials say a gunman opened fire at multiple locations in Montenegro, killing a dozen people before turning the gun on himself.

The New Year’s Day shooting shocked a country where gun ownership is widespread. Montenegro’s government began a three-day mourning period Thursday after a gunman opened fire on New Year’s Day — killing 12 people, including two children, across several locations.

Montenegrin Prime Minister Milojko Spajic called the rampage a "terrible tragedy" and declared three days of national mourning.