At least six more people were injured, the news agency reported.
A witness told RTCG that the shooter “indiscriminately shot people as he walked through the street.”
Authorities say they have identified the attacker — said to be a 34-year-old man — whose rampage was brought to an end when he was shot dead by a civilian.
No reason has been given for the attack.
The head of Clinical Center of Montenegro Ljiljana Radulovic said that three of the injured victims are in the hospital in a critical condition.
Montenegro’s President Milo Đukanović tweeted on Friday that he was “deeply shaken” by the news.
“I express my sincerest condolences to the bereaved families, to all those who lost their loved ones. All of us as a society must stand in solidarity with them in these difficult times,” Đukanović said on Twitter.