China's leader has said the coronavirus epidemic is the communist country's "largest public health emergency" since its founding, as the deadly outbreak continued its relentless global expansion. 

Italy reported a spike in cases today as a third person died, while Iran said eight people had died from the virus there, prompting travel bans from neighbouring countries.

The virus has so far killed more than 2,400 people, with some 80,000 infected globally, though China remains by far the worst hit. 

China's President Xi Jinping said the epidemic was the "largest public health emergency" since the founding of the People's Republic in 1949. 

"This is a crisis for us and it is a big test," he said today in remarks carried by state television.

In a rare admission, he added China must learn from "obvious shortcomings exposed" during its response, speaking at a meeting to coordinate the virus fight.

China has been praised by the World Health Organization (WHO) for its response to the epidemic, but has come under fire at home for silencing early warnings from a whistleblower doctor who has since died from the virus.

The outbreak in China remains concentrated in the city of Wuhan - locked down exactly one month ago - where the virus is believed to have emanated from a live animal market in December.

China's infection rate has slowed, but flip-flopping over counting methods has sowed confusion over its data.

There also was growing concern over the difficulty of detecting the virus.

South Korea

Mr Xi's comments come as South Korea said it was raising its alert to the "highest" level, after the number of infections nearly tripled over the weekend to 602.

The country now has the most infections outside of China, apart from the Diamond Princess cruise ship docked in Japan.

"The next few days will be crucial," South Korean President Moon Jae-in said, without specifying what measures would be rolled out.

South Korea reported 169 new cases and three deaths on Sunday, taking the countrywide fatality toll to five.

Yonhap news agency later reported a sixth death.

Around half of the country's cases have been linked to the Shincheonji Church of Jesus sect in the southern city of Daegu, where thousands of members have been quarantined or asked to stay at home.

The new cases also included a Samsung Electronics employee at a plant in Gumi city, leading the tech giant to suspend operations there until tomorrow.

Iran

Elsewhere, Iran ordered the closure of schools, universities and cultural centres across 14 provinces following eight deaths in the country - the most outside East Asia.

Iran's outbreak surfaced Wednesday and quickly grew to 43 confirmed infections.

"The concern is... that we have seen... a very rapid increase (in Iran) in a matter of a few days," said Sylvie Briand, director of the WHO's global infectious hazard preparedness department.

The sudden rise in cases prompted a flurry of travel restrictions in the region.  

Four immediate neighbours of the Islamic republic - Turkey, Pakistan, Afghanistan and Armenia - said  they would close land borders, while three imposed restrictions on air traffic, amid growing regional concerns about the spread of the virus.

Iraqi and Kuwaiti authorities have already banned travel to and from Iran.

Japan

Japan confirmed that a woman who tested negative and disembarked from the virus-stricken Diamond Princess cruise ship off Japan later tested positive. Similar instances have been reported elsewhere.

A third passenger from the ship died Sunday, Japan's health ministry said, without specifying if it was as a result of the virus.

Japan has been criticised over its handling of cases aboard the cruise ship.

Many passengers were allowed to disembark without being properly tested or despite having close contact with infected people.

More than 1,000 crew remain on board and are expected to serve a 14-day quarantine.