The window of opportunity to contain a mass global outbreak of the killer coronavirus is "narrowing", the head of the World Health Organisation has warned.
Worried Dr Tedros Adhanom Ghebreyesus has expressed fears of a pattern of infection as countries across the world see hundreds of cases of the virus - with no clear link to source country China.
Iran today reported two more deaths, bringing the total to four, and said the fatalities were from among 13 new confirmed cases of the virus.
Concerns over the spread of the virus prompted Iran to close all schools and Shiite seminaries in Qom, about 130 kilometres (80 miles) south of Tehran.
Officials fear the virus may have spread to "all Iran's cities", the BBC reports.
While Italian authorities said the number of people infected with the new coronavirus from China has more than quadrupled due to an emerging cluster of cases in the country's north.
Many of the new cases represented the first infections in Italy acquired through secondary contagion and brought the country's total to 17.
Dr Tedros said the pattern of infection outside of China was worrying, and the new cases in Iran were "very concerning".
He said: "We are concerned about the number of cases with no clear epidemiological link, such as travel history to or contact with a confirmed case."
But he insisted there was still a "fighting chance" of stopping the spread of the virus and called on all nations to do more to fight outbreaks.
The first to fall ill in northern Italy met with someone who had returned from China on January 21 without presenting any symptoms of the new virus, called Covid-19, health authorities said.
The 38-year-old Italian man is in hospital in the northern town of Codogno in a critical condition.
The man's wife and a friend of his also tested positive for the virus.
Three patients at the hospital where he went with flu-like symptoms a few days ago also have infections.
Five nurses and doctors contracted the virus as well.
Italian health minister Roberto Speranza said Italy is now seeing the same sort of "cluster" of cases that Germany and France have seen.
The mayor of Codogno has issued a decree ordering the closure of all restaurants, coffee bars, schools and public gathering spots such as discos and gyms.
The Health Ministry advised area residents to stay home as a precaution.
Local officials in another town, Casalpusterlengo, ordered local schools closed until Tuesday.
A third town, Castiglione d'Adda, said its libraries, public offices, gyms and waste depots would be closed as a health precaution.
"In other parts of the world, and also in China, it has been demonstrated that this system (of self-isolation) helps in a substantial way to block the spread," Lombardy regional president Attilio Fontana said.
"But we must not let ourselves be overcome by panic."
The Codogno hospital closed its emergency room, and staff were seen wearing masks as movers brought in new beds and furniture as the quarantine got under way.
Despite the calls for safeguards, Italians were having a hard time finding protective face masks.
A sampling of Milan pharmacies reported selling out weeks ago, as did a pharmacist in Codogno.
In Iran, Minoo Mohraz, a health ministry official, said the virus "possibly came from Chinese workers who work in Qom and travelled to China".
A Chinese company has been building a solar power plant in Qom.
In Lebanon, health minister Hamad Hassan reported the Mediterranean country's first case of the new virus.
At a news conference in Beirut, he said the patient was a 45-year-old woman who arrived on Thursday on a flight from Qom.
He said the woman was in "good health" and the ministry was also following up on the cases of two other people suspected of having the illness.
The woman and two other suspected victims were quarantined at the Rafik Hariri government hospital in Beirut.
Concerns over the spread of the virus, which originated in central China, prompted authorities in Iran this week to close all schools and Shiite seminaries in Qom, about 130 kilometres (80 miles) south of Tehran.
Earlier news reports said Iran had recently evacuated 60 Iranian students from Wuhan, the Chinese city at the epicentre of the epidemic.
The students were quarantined upon their return to Iran and were discharged after 14 days without any health problems.
Qom is a popular religious destination and a centre of learning and religious studies for Shiite Muslims from inside Iran, as well as Iraq, Pakistan, Afghanistan and Azerbaijan.
It is also known for its cattle farms.
Iran once relied heavily on China to buy its oil and some Chinese companies have continued doing business with Iran in the face of US sanctions.
Unlike other countries - such as Saudi Arabia, which barred its citizens and residents from travelling to China - Iran has not imposed such measures on travel there.
The new virus emerged in China in December.
Since then, more than 76,000 people have been infected globally, with more than 2,200 deaths being reported, mostly in China.
There have been few virus cases in the Middle East so far.
Nine cases have been confirmed in the United Arab Emirates, which is a popular tourist destination, and one case in Egypt.
Of the nine in the UAE, seven are Chinese nationals, one is a Filipino and another an Indian national.
Iran's neighbour Iraq, which has reported no cases of the virus, took measures to contain it by suspending visas on arrival for Iranian passport holders and direct flights between the two countries.