BREAKING NEWS

Four people were killed and around 20 more were injured when a violent downpour caused a flash flood in northen Italy late on Saturday.

Water swept through a summer festival near the town of Refrontolo, about 50 kilometres north of Venice.

Several people remain missing.

About 100 people had gathered when a thunderstorm hit, sending a wall of water and mud through the festival.

Eye witnesses told local media that the deluge was so strong that people were grabbing onto trees to prevent themselves being swept away.

Local governor Luca Zaia, who visited the area on Sunday, said a state of emergency was being declared.