The number of confirmed coronavirus cases in Iran rose by 2,089 to 402,029, a health ministry spokeswoman told state TV on Sunday.
The country also recorded 128 new deaths in the past 24 hours.
The new fatalities raised the official death toll to 23,157, Sima Sadat Lari said.
Last week, Iran, one of the worst-hit countries in the Middle East, began the new school year despite concerns by medical professionals and many parents over increased spread of the virus.
Meanwhile, the World Health Organization has warned that Middle Eastern countries, which had kept their coronavirus infection rates under control, were now facing significant upticks, confirming that cases have topped two million.
The caseload for the 21 countries has more than doubled since July 1, the UN agency said.
It is now six months since the WHO declared the novel coronavirus a pandemic.