All schools, educational centres, banks and governmental offices in at least 20 provinces will be shut on Saturday because of the cold, media reports said.

In addition to Tehran, other provinces affected include East and West Azerbaijan in the northeast, Kurdistan and Kermanshah in the west, Gilan in the north, Markazi in central Iran and Kerman in the south.

The decision follows weather forecasts predicting a sharp drop in temperature.

State television predicted that some provinces would experience temperature falls of up to 12 degrees Celsius, starting on Friday and continuing until the middle of next week.

The official IRNA news agency said the average temperature in the capital is expected to range between six and minus three degrees Celsius over the next few days.

It cited state meteorologists as saying some areas in northwestern Ardabil province will experience temperatures as low as minus 18 degrees Celsius.

The cold snap coincides with heavy snowfall and rain in western and northern provinces on Thursday and Friday.

Authorities in Gilan province ordered the emergency evacuation of three neighbourhoods of Rasht city on Friday when a river burst its banks.

Iran often implements closures during the cold season, citing extreme conditions and fuel shortages.

In December, Iran suspended operations at several power plants over fuel shortages that only intensify during cold weather because of increased demand.