The Iranian government ordered on Tuesday the evacuation of 70 villages in the oil-rich southwestern province of Khuzestan over the risk of floods, reported the IRNA news agency.
The villages were close to the Dez and Karkheh rivers, Shush county governor Adnan Qazi said, according to IRNA.
At least 45 people were killed in the past two weeks in flash floods in northern and southern Iran after the heaviest rains in at least a decade.
Iran has announced a state of emergency in southern provinces threatened by flooding and has evacuated dozens of villages already.
Floods have affected at least 23 out of Iran’s 31 provinces since heavy downpours began on March 19.
Western and southwestern parts of the country are expected to bear the brunt of the storms in the days ahead.
Foreign Minister Mohammad Javad Zarif said US sanctions imposed on Tehran by the Trump administration last year have hampered successful rescue efforts for flood-stricken areas.
He tweeted late on Monday that America's "maximum pressure" policy on Iran "is impeding aid efforts by #IranianRedCrescent to all communities devastated by unprecedented floods."
The sanctions, he said, have prevented Tehran from getting badly needed equipment, including relief helicopters. "This isn't just economic warfare; it's economic TERRORISM," he tweeted.
Local authorities in the stricken areas have repeatedly asked for more helicopters to reach remote and cutoff locations.
Britain and Germany have offered to send help, including boats and safety equipment.
Iranian media reports said the floods have cut off some 80 intercity roads, as well as roads to nearly 2,200 villages, and that electricity and communications with many places, including in western Ilam and Lorestan provinces, have been cut.
State media said officials have warned about the possibility of dams breaking and have ordered emergency water discharges from reservoirs to prevent a catastrophe.
Triggered by heavy rainfall, several rivers have burst from their banks. Emergency services are advising people to postpone unnecessary intra-city commutes, as well as trips to western and southern Iran, including Khuzestan province.
The floods have hit Iran particularly hard, coming against the backdrop of a spiraling economic crisis. President Donald Trump's decision last year to withdraw from the Iranian nuclear deal with world powers and restore crippling economic sanctions have caused the Iranian currency, the rial, to plummet in recent months, sending prices skyrocketing and wiping out many people's life savings.
The floods first began in the second half of March in the northern provinces of Golestan and Mazandaran and later spread. Iran has seen a decades-long drought but the latest flooding has also been blamed on widespread disregard of safety measures and construction of buildings and roads near the rivers.
Last year, at least 30 people were killed by flash floods in East Azerbaijan province.
