* South Korea sees 169 new infections, 2 new deaths
* Chinese authorities warn against gatherings, complacency* Coronavirus spread concentrated mostly in Hubei
* Japan PM wants comprehensive plan to curb virus spread
* WHO most concerned about cases with no China link
International concern about the spread of coronavirus outside China grew on Sunday with sharp rises in infections in South Korea, Italy and Iran.
The government in Seoul put the country on high alert after the number of infections surged over 600 with six deaths. A focal point was a church in the southeastern city of Daegu, where a 61-year-old member of the congregation with no recent record of overseas travel tested positive for the virus.
In Italy, the number of cases jumped to above 130 from just three before Friday. Authorities sealed off the worst affected towns and banned public gatherings in much of the north, including halting the carnival in Venice, where there were two cases, to try to contain the biggest outbreak in Europe.
Italian health authorities were struggling to find out how the virus started. "If we cannot find 'patient zero' then it means the virus is even more ubiquitous than we thought," said Luca Zaia, the regional governor of the wealthy Veneto region.
Iran, which announced its first two cases on Wednesday, said it had confirmed 43 cases and eight deaths, with most of the infections in the Shi'ite Muslim holy city of Qom.
China, which has seen the vast majority of cases, reported 648 new infections. But only 18 were outside of Hubei province, the lowest number outside the epicentre since authorities began publishing data a month ago and locked down large parts of the country.
"At present, the epidemic situation is still severe and complex, and prevention and control work is in the most difficult and critical stage," President Xi Jinping said.
State run television urged people to avoid complacency, drawing attention to people gathering in public areas and tourist spots without wearing masks.
The virus has killed 2,442 people in China, which has reported 76,936 cases, and has slammed the brakes on the world's second largest economy. It has spread to some 26 other countries and territories, with a death toll of around two dozen, according to a Reuters tally.
"Despite the continuing decline in reported cases from China, the last two days have seen extremely concerning developments elsewhere in the world," said Paul Hunter, professor of medicine at Britain's University of East Anglia.
The coronavirus has been fatal in 2% of reported cases, with the elderly and ill the most vulnerable, according to the World Health Organization (WHO), which said on Saturday it was worried by the detection of infections without a clear link to China.
In South Korea, Catholic churches in Daegu and Gwangju have suspended services and other gatherings, while churches elsewhere saw declines in attendance on Sunday, especially among the elderly.
"If the situation gets worse, I think we'll need to take more measures," said Song Gi-young, 53, wearing a face mask at church.
Heo Young-moo, 88, expressed frustration.
"Devotees shouldn't go to any risky places ... Hasn't it become so widespread because those people didn't get checked?"," he said.
South Korea's president said raising the disease alert to the highest level allowed authorities to send extra resources to Daegu city and Cheongdo county, which were designated "special care zones" on Friday.
It also enables the government to forcibly prevent public activities and order the temporary closure of schools, the Yonhap News Agency said, although the government gave no immediate details on what steps could be taken.
Health officials reported 169 new infections, bringing the total to 602.
Concern about the reach of the coronavirus also grew in Europe and the Middle East.
In Italy, schools and universities were closed and some soccer matches postponed in the affected northern regions of Lombardy and Veneto, the country's industrial heartland.
Almost a dozen towns in Lombardy and Veneto with a combined population of some 50,000 have effectively been placed under quarantine, with locals urged to stay home and special permission needed to enter or leave the designated areas.
The European Union said it had confidence in the Italian authorities. "We share concern for possible contagion (but) there is no need to panic," the bloc's Economic Affairs Commissioner Paolo Gentiloni told reporters.
Iran reported a total of 43 infections, with eight deaths - all since Tuesday. Saudi Arabia, Kuwait, Iraq, Turkey and Afghanistan imposed travel and immigration restrictions on Iran.
The potential economic impact of the disease was prominent at a meeting of G20 finance ministers in Riyadh.
The International Monetary Fund chief said China's 2020 growth would likely be lower at 5.6%, down 0.4 percentage points from its January outlook, with 0.1 percentage points shaved from global growth.
Xi highlighted the importance of fighting the epidemic in the capital Beijing, which has recently required people arriving from elsewhere in China to be quarantined at home for 14 days.
He said it would have a relatively big, but short-term impact on the economy and that Beijing would step up policy adjustments to help cushion the blow.
In Japan, where the government is facing growing questions about whether it is doing enough to counter the virus, authorities had confirmed 773 cases by early Sunday evening.
Most of them were from a cruise ship quarantined near Tokyo, the Diamond Princess. A third passenger, a Japanese man in his 80s, died on Sunday.
Prime Minister Shinzo Abe instructed government agencies to urgently prepare medical provisions and draft a comprehensive plan to curb the spread.