Twelve people have also gone missing, the source said.
The flood hit Sijan area along the Karaj-Chalus Road where traffic was heavy since people were heading back home from a four-day holiday.
Also called Road 59 or Kandovan Road, Chalus Road is an important route for people of Tehran and Alborz provinces, a large number of whom drive to popular tourist attractions in the north of Iran on weekends and for holidays.
Darkness complicated rescue operations and it was impossible to estimate the extent of the damage during the early hours of the flood, the rescue official said.
Reports also say that 20 people have been killed in another similar incident in an area to the northwest of Tehran called Emamzadeh Davood.
Heavy flood and landslide took 20 lives and blocked the road on some 2500 cars on a nearby road, the Fars news agency reported.
The report further said that two Chinese-national workers who used to work on gardens in the area have gone missing and heavy damage has been done to properties in the area.
More about:
