Gholamhossein Ejei will replace Ebrahim Raisi, who takes office in August as president after winning June 18 election.
Two young men were shot and killed during a second night of protests over water shortages in southwest Iran.
Iran is facing its worst drought in 50 years, with protests breaking out in several cities and towns in Khuzestan province over the water crisis, which has affected households, devastated agriculture and livestock farming, and led to power blackouts.
The deadly incidents came on Friday in the Khuzestan town of Shadegan.
Omid Sabripour, the county’s acting governor, speaking to IRNA on Saturday, blamed the first death on “opportunists and rioters”.
“During the rally, rioters shot in the air to provoke the people, but unfortunately one of the bullets hit a person present at the scene and killed him,” he said.
In separate comments to the ISNA news agency, Sabripour said the shooting was directed at both the demonstrators and security forces.
He added that the victim was a “30-year-old passerby” and that those responsible were identified.
A second man was later reported to have been killed during the protests.
Iranian media broadcast a video of the father of the first victim, Mostafa Naimawi, who said his son was shot by rioters and not by government security forces.
“My son was not a trouble maker and had nothing to do with riots and disturbances,” the father, who was not identified by name, said in Arabic on the video that provided a Farsi translation.
The second victim was identified as Ghasem Khozeiri, an 18-year-old man. State media published an interview with his family, in which his uncle, who was not identified by name, said Khozeiri was coming back from work at night when he was shot and later died of his injuries.
“He managed to get himself home while he was all bloody … he couldn’t say who his attacker was,” his uncle said.
Videos posted on social media have shown protesters setting fire to tyres to block roads and security forces trying to disperse crowds as shots were heard.
During some of the protests, people vented their anger with Supreme Leader Ali Hosseini Khamenei, chanting “Death to the dictator” and “Death to Khamenei”.
Some were arrested on Friday night, with a manhunt launched for the others.
Earlier this month, President Hassan Rouhani said the drought was “unprecedented”, with average rainfall down 52 percent compared to the previous year.
Khuzestan MP Abdollah Izadpanah warned on Friday that “Khuzestan’s insecurity means a lack of security for the whole country”.
He blamed the water shortages on “mistakes and unjustified decisions” such as the extraction of water from Khuzestan’s rivers to other provinces, ISNA reported.
The government, judiciary and President-elect Ebrahim Raisi have said they are addressing the water shortage issue and the government on Friday sent a delegation to the province to alleviate the situation.
This month, rolling blackouts began in the capital, Tehran, and several other large cities, which officials blamed on the effects of the drought on hydroelectric power generation, as well as surging demand.
Power cuts in the peak summer months are not uncommon in Iran, but the continuing drought has intensified the situation.
Khuzestan is home to a large Sunni Arab minority, which has frequently complained of marginalisation in mainly Shia Iran.
In 2019, the province was a hotspot of anti-government protests that had shaken other areas of the Islamic republic.
Over the years, blistering summer heatwaves and seasonal sandstorms blowing in from Saudi Arabia and neighbouring Iraq have dried up Khuzestan’s once-fertile plains.
Scientists say climate change amplifies droughts, and their intensity and frequency, in turn, threaten food security.
The country is also dealing with a fifth wave of COVID infections after the Delta variant started spreading through the southern provinces and is now dominant nationwide.