Several people have been killed and at least 10 injured in the second mass shooting in Serbia in as many days.
The gunman reportedly fired an automatic weapon from a moving vehicle near a village 60km (37 miles) south of Belgrade.
Unconfirmed reports say that the perpetrator is still on the run.
Earlier this week, a teenager killed eight students at a school in Belgrade in the worst mass shooting to occur in Serbia in years.
On Friday morning, Serbian media said that special police forces had arrived at the villages of Mladenovac and Dubona, where the latest massacre occurred.
Photos from the scene show police officers stopping cars at checkpoints as they try to locate the gunman. A helicopter, drones and multiple police patrols also searched for the suspect in the area around Dubona.
Reports on local media say a 20-year-old man started firing at people with an automatic weapon after having an argument with a police officer in a park in Dubona on Thursday evening.
The man is then said to have proceeded to shoot people from a car, killing at least eight people and wounding many more.
The minister of health, Danica Grujičić, and the head of the Security Intelligence Agency, Aleksandar Vulin, reportedly travelled to the area in the early hours of Friday.
On Wednesday, a thirteen-year-old boy shot dead eight fellow pupils at his school in Belgrade, as well as a security guard. It prompted the Serbian government to propose tighter restrictions of gun ownership.
Mass shootings are comparatively rare in Serbia, which has very strict gun laws, but gun ownership in the country is among the highest in Europe.
The western Balkans are awash with illegal weapons following wars and unrest in the 1990s. In 2019, it was estimated that there are 39.1 firearms per 100 people in Serbia – the third highest in the world, behind the US and Montenegro.