Iran could soon be facing a coronavirus catastrophe as experts predict that unless citizens begin to follow advice, up to 3.5 millions Iranians could die.

The startling statistic comes from researchers at the renowned Sharif University of Technology in Tehran, who created a computer simulation to test different scenarios for the further spread of COVID-19 across the country.

The results showed that if Iranians followed the regime’s advice fully and immediately, the peak of the epidemic would be reached in early April, and the death toll would be limited to 12,000 in a population of over 81 million people.

The regime has warned citizens to avoid crowds and, where possible, to stay in their homes. Health officials have also warned against non-essential travel, saying that anyone who ignores the advice is “inviting death.”

If citizens somewhat cooperate, then the death toll would be 110,000, but if citizens ignore the warnings completely, then the outbreak would not peak until June and up to 3.5 million people (4.3% of the population) would die.

Details of the dire warning were carried on Iranian state television on Tuesday. Just hours earlier, large crowds of hard-line Shiite faithful stormed two religious shrines in a clear indication that at least parts of the population were not willing to adhere to restrictions.

Angry crowds stormed into the courtyards of Mashhad's Imam Reza shrine and Qom's Fatima Masumeh shrine on Monday night, where crowds typically pray 24 hours a day, seven days a week, touching and kissing the shrine.

Earlier on Monday, the regime announced the shrines would be closing, after weeks of warnings by health officials.

Iran reported another 147 deaths on Wednesday, bringing the total to 1,135 with over 17,300 infections confirmed.

But experts have been warning for weeks that Tehran is dramatically underreporting the numbers of deaths and infections in the country. The World Health Organization said on Tuesday that it suspected the real figures are five times higher.

Iranian authorities are belatedly trying to get a handle on the outbreak, having delayed imposing any restrictions last month in order to boost attendance at an annual march marking the anniversary of the 1979 Revolution on Feb. 11 and local elections on Feb. 21.

Officials have implemented new checks for people trying to leave major cities ahead of Nowruz, the Persian New Year, on Friday, but have stopped short of imposing lockdowns seen in other hard-hit countries like China and Italy.

Iranian President Hasan Rouhani has defended his government’s reaction, and Tehran’s mayor says putting major cities into lockdown is just not feasible.

“We have neither the capacity nor the ability to put Tehran under quarantine," Pirouz Hanachi told the Mehr News Agency. “We can't take care of quarantined people. That is in part because of the sanctions.”

The U.S. has been criticized for making the situation in Iran worse by not lifting its severe economic sanctions on the country. Rather than lifting sanctions, Secretary of State Mike Pompeo announced fresh ones on Tuesday, in a bid to get Tehran to release U.S. detainees.

Even if the International Monetary Fund grants the $5 billion emergency loan Tehran has requested to deal with the outbreak, it may struggle to buy medical supplies because of the severe sanctions imposed by Washington.

Rouhani recently wrote to world leaders to say Iran’s fight against the coronavirus has been “severely hampered by U.S. sanctions” while Iranian foreign minister Javad Zarif accused the U.S. government of “medical terrorism.”