The outbreak has claimed 77 lives and infected more than 2,300 people across the country.
The new coronavirus is well-established in Iran, UN health officials said on Tuesday, warning that a lack of protective gear for healthcare workers was complicating efforts to control the outbreak.
"It is not an easy situation," Michael Ryan, who heads the World Health Organization's emergencies programme, told reporters in Geneva.
The outbreak which has claimed 77 lives and infected more than 2,300 people across the country is affecting multiple cities, he pointed out.
"Like in some other countries, the disease is now well-established," he said.
Ryan said rooting out the virus in countries where it has become established "is not impossible" but "it is difficult".
"Doctors and nurses have concerns that they do not necessarily have enough equipment, supplies, ventilators, respirators, oxygen," he said of Iran.
The WHO said on Tuesday that supplies of protective gear worldwide were rapidly depleting, threatening the overall response to the outbreak, which has killed more than 3,100 people -- mostly in China.
But the problem is particularly serious in Iran.
"Those needs are more acute for the Iranian health system then they are for most any other health system," Ryan said.
In a first step towards addressing the problem, a WHO team of experts arrived in Iran on Monday to help with the response, bringing with them medical supplies and enough laboratory kits to test roughly 100,000 people.
Iran has shut schools and universities, suspended major cultural and sporting events and cut back on work hours in response to the outbreak.
On Tuesday, it announced another 11 deaths and 835 new infections -- the biggest increase in a single day since the COVID-19 outbreak began nearly two weeks ago.
National emergency services chief Pirhossein Kolivand was the latest high-profile official to contract the illness, a spokesman for the services told AFP.
Mohammad Mirmohammadi, 72, a member of the Expediency Council which advises Iran's supreme leader, died from the virus this week, according to Tasnim news agency.
The country's deputy health minister Iraj Harirchi fell ill with COVID-19 last week.
Ryan said that while the spike in numbers could appear to be a very bad thing, it reflected "a more aggressive approach to surveillance and case detection".
"Things tend to look worse before they get better," he said, adding: "You have to find your problem, you have to recognise your problem and then deal with your problem."
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)