All four deaths occurred in Moknine, in the Monastir governorate, where "two people were swept away by floodwaters, while a woman drowned in her home", said Khalil Mechri, a civil defence spokesman.

Abderazak Rahal, head of forecasting at the National Institute of Meteorology (INM), told AFP some Tunisian regions hadn't seen so much rain since 1950.

"We have recorded exceptional amounts of rainfall for the month of January," Rahal said, with the regions of Monastir, Nabeul and greater Tunis being the hardest hit.

Striking images of cars stranded as torrents of water rushed through streets have widely circulated on social media.

Reports said authorities have suspended classes in several regions due to the bad weather. Transportation has also been interrupted in several parts of the country.

The Tunisian army was taking part in rescue operations, a Defence Ministry source told AFP on condition of anonymity.

"It is its duty, since it's part of the national commission for combating natural disasters," the source said.

Mahrez Ghannouchi, another INM official, said in a Facebook post the situation was "critical" in some regions.

The tourist village of Sidi Bou Said, on the outskirts of Tunis, has recorded 206 millimetres of rain since Monday evening, according to the INM.

While the rainfall has proved record-breaking, Tunisian streets often flood after heavy downpours, largely owing to the state of the country's infrastructure.

Drainage and stormwater networks are often old and poorly maintained, particularly in rapidly expanding urban areas, with waste sometimes clogging the system.

Rapid urbanisation of some areas has also led to less rainwater being absorbed into the ground, increasing runoff.

The latest dramatic deluges come as Tunisia grapples with a seven-year drought, worsened by climate change and marked by a sharp decline in water reserves in dams across the country.

The country has seen severe water stress, particularly affecting agriculture and drinking water supplies, with cuts imposed in several regions during the summer.