Fires near the southwestern Serbian town of Cacak swept through hillsides and cornfields dried to a crisp by scorching temperatures, forcing the evacuation of the villages of Srezojevci, Gornja Gorevnica and Miokovci near Cacak, Reuters reported.
Fires are threatening 300 homes and three people have been hurt, Beta news agency quoted Predrag Maric, head of the ministry's Emergencies Department, as saying.
A Russian Beriev Be-200 fire-fighting plane, with a capacity of 12 tonnes, on Friday joined a Russian helicopter that has been in action for days trying to extinguish the fires on Suvobor mountain.
The Serbian Interior Ministry said it had called up the army and the police gendarmerie to fight fires threatening Srezojevci, Gornja Gorevnica and Miokovci.
The state news agency Tanjug quoted Matic as saying the situation was "extremely serious."
Between 400 and 500 hectares of land is on fire, said Dragisa Brocic, head of the Moravica District Emergencies Department.
All of Southeast Europe is in a heatwave that has seen temperatures top 40 degrees Celsius, triggering hundreds of wildfires. Serbia and neighbouring Bosnia appear to be worst hit, said Reuters.