An Iranian deputy health minister has warned of a "resurgence" of novel coronavirus cases in several parts of the country following reduced observance of health protocols.
Deaths and infections have been on a rising trajectory in Iran since hitting a months-long low at the beginning of September.
"Whenever health protocols are less observed, the disease begins to surge," Alireza Raisi was quoted as saying on the ministry's website.
"A small number of people have not been careful and went on trips during the recent holidays," he added.
"This is while travelling has proven to be the cause of the disease's resurgence, and sadly, (the surge) is happening."
According to the official, the rise in infections can be seen in the number of hospitalizations in Tehran province, which last week doubled to around 1,800 per day.
Raisi added that "some other provinces" are also in danger, without naming them.
Health ministry spokeswoman Sima Sadat Lari said on Tuesday that 2,705 more people had tested positive for the Covid-19 disease in the past 24 hours.
This raises the total number of cases identified to 407,353.
Another 140 people died from the disease during the same period, bringing the overall death toll to 23,453.
The anti-coronavirus coordinator for the capital, Alireza Zali, warned of a "third wave" of the virus on Monday, AFP reported.
"Forecasts show us moving toward the third wave of the coronavirus, and it seems the wave will take shape in Tehran much earlier than other provinces," he was quoted as saying by IRNA news agency.
Iran has made wearing masks mandatory in enclosed public spaces and repeatedly called on Iranians to refrain from travelling to contain the virus' spread.