Witnesses were quoted as saying the attacker shot randomly at people in the street in the town of in Cetinje before being shot dead by police.
At least 11 people were killed on Friday in a mass shooting in central Montenegro following a family dispute, the Balkan country's public broadcaster RTCG said.
"Eleven people were killed, while six were injured, including a police officer," the source said on Friday, adding that the assailant was among the dead. A police officer speaking on condition of anonymity confirmed the toll to AFP.
The tragedy took place in the city of Cetinje, 36 kilometres west of the capital Podgorica, after the gunman was involved in a family dispute, RTCG said.
The assailant was killed after opening fire on police officers, the broadcaster said.
RTCG, quoting witnesses, said the attacker was randomly shooting at people walking in the street, including at children. Four of the wounded were transferred to a hospital in Cetinje while two others with serious wounds were sent to the Clinical Center in Podgorica.
It was the deadliest shooting in decades in Montenegro, and occurred at the height of the tourist season in the country known for its picturesque beaches bordered by mountains.
Cetinje, the former royal capital, is located in a mountainous valley that has experienced economic stagnation in recent decades.