The incident occurred in the city of Krymsk in the Krasnodar region.
Russian authorities say a gunman has killed three people in a shooting before turning the weapon on himself.
The 66-year-old man reportedly opened fire on Thursday in the southern city of Krymsk in the Krasnodar region, around 1,200 kilometres south of Moscow.
Alexander Runov, a spokesman for the regional interior ministry, said the gunman shot two employees at a local medical centre and then went outside, shooting at passersby on the street and killing one other person.
"According to preliminary data, a 66-year-old local resident fired several shots at his friends, who died from their injuries on the spot," Russia's Investigative Committee said in a statement.
"In addition, the man shot another man with the same gun, killing him," it added.
"A 61-year-old man was also wounded and is currently hospitalised. After the incident, the man took his own life."
An investigation is underway to determine the gunman's motive.
Runov was quoted as saying that tensions over the man's divorce could be behind the shooting.