Iran's death toll from the coronavirus has reached 1,135, with 147 deaths over the past 24 hours -- the highest 24-hour rise yet -- state TV reported on March 18, as President Hassan Rouhani defended his government's response to the outbreak.

Iran has been the hardest-hit country in the Middle East, with a total of 17,361 confirmed cases, roughly 90 percent of the region's cases.

A World Health Organization official said Monday that due to scarcity of test kits, the real number of infection cases and death in Iran could be five times higher.

Radio Farda's independent estimate based on various local reports from Iran puts the number of deaths at 1,774.

Iran has been accused of acting too slowly and of even covering up initial cases.

But Rouhani on March 18 rejected criticism of his government's response to the coronavirus outbreak, telling a government meeting that authorities have been “straightforward" with the nation, and that it had announced the outbreak as soon as it learned about it on February 19.

"We spoke to people in a honest way. We had no delay,” Rouhani said.

Government officials pleaded for weeks with clerics to completely close crowded holy shrines to slow the spread of the coronavirus. The government finally shut down the shrines this week.

“It was difficult of course to shut down mosques and holy sites, but we did it. It was a religious duty to do it,” Rouhani said.

The outbreak has cast a shadow over the Persian New Year, Norouz, that begins on March 20.

Iran warned on March 17 that “millions” could die in the Islamic republic if people keep traveling and ignore health guidance.