A gunman has killed 12 people, including two children, in a series of shootings in southern Montenegro.

Authorities said the man – later identified as Aco Martinovic, 45 – had been drinking heavily all day when got into an altercation with another guest at a restaurant in the Cetinje area around 17.30 (16.30 GMT) on New Year’s Day.

After the argument, Martinovic went home to retrieve a weapon, then returned to the restaurant and began his rampage, killing several customers.

Martinovic then drove to five other locations and shot several more people, including members of his immediate and extended family. The restaurant owner and his children, aged 10 and 13, were also killed.

Police tracked Martinovic down after an hours-long manhunt. When they ordered him to drop his weapon during a stand-off, he fatally injured himself and died as he was being transported to hospital.

The government has declared three days of national mourning from Thursday, with Prime Minister Milojko Spajic saying the shooting had “shrouded our country in black”.

Interior Minister Danilo Saranovic called the incident a “consequence of disturbed interpersonal relations”, according to AFP news agency.

Four people were taken to hospital after being seriously wounded in the shooting. Three of them were in a stable but life-threatening condition, authorities said, while one was in critical condition.

Writing on social media, the prime minister said: “This senseless act has caused immeasurable sadness and bitterness in each of us. There are no words of comfort.”

Milojko Spajic said the country’s security council would hold an emergency meeting on Thursday to “urgently consider all options” to protect the public, including a complete ban on the possession of weapons.

Mass shootings are comparatively rare in the small Balkan nation.

In 2022, a man killed several people, including children, in Cetinje following a family dispute.