The attacker, when he was surrounded by the police after several hours of pursuit, shot himself in the head and died before being taken to the hospital.
The shooting reportedly took place in Cetinje, about 30 kilometers northwest of the capital Podgorica.
Police identified the shooter as 45-year-old Aco Martinovic. After a fight with a bar patron, he went home, took a gun, returned and killed the bar owner and his children, before shooting his family members in three other places, Montenegro’s Interior Minister Danilo Šaranović said.
He also said that before that Martinovic had been drinking alcohol all day.
Four people were injured in the shooting and taken to the hospital, three of them are in a life-threatening condition.
The Prime Minister of Montenegro, Milojko Spajic, has declared three days of mourning in the country.
TV channel RTCG reported that Martinovic was previously detained in connection with the illegal possession of weapons.
(According to the latest information, the number of those killed has been clarified, paragraph 6 has been added)