SEOUL, Korea, Republic Of - South Korea's president said Sunday that he was putting his country on its highest alert for infectious diseases, ordering officials to take “unprecedented, powerful” steps to fight a soaring viral outbreak, while a continent away in Italy, authorities battled to contain Europe's first major outbreak of the virus.

China also reported hundreds more infections for a total of about 77,000, and Iran raised its death toll from the virus to eight - the highest toll outside of China. While the number of patients worldwide is increasing, some virus clusters have shown no link to China and experts are struggling to trace where those clusters started.

The Iranian health ministry said there were now 43 confirmed cases in Iran, which did not report its first case of the virus until Wednesday.

In Italy's northern Lombardy region, which includes the nation's financial capital, Milan, the governor announced Sunday that the number of confirmed cases stood at 110. Italy now has 152 cases, the largest number outside of Asia, including three deaths, the most recent on Sunday.

Venice, which is full of tourists for Carnival events, reported its first two cases, said Veneto Gov. Luca Zaia, whose region includes the lagoon city. It wasn't immediately known if the two infected had participated in Carnival festivities.

As Italy scrambled to check the spread of the virus, authorities announced that all Carnival events had been called off as well as major league soccer matches in the stricken region. Cinemas and theatres were also ordered shuttered, including Milan's legendary La Scala.

Warning that China's virus epidemic is “still grim and complex,” President Xi Jinping called for more efforts to stop the outbreak, revive industry and prevent the disease from disrupting spring planting of crops.

Xi defended the ruling Communist Party's response as “timely and effective” in a video conference with officials in charge of anti-disease work, according to the official Xinhua News Agency.

“The current epidemic situation is still grim and complex,” Xinhua cited Xi as saying. “Prevention and control are at the most critical stage.”

South Korean President Moon Jae-in said his government had increased its anti-virus alert level by one notch to “Red,” the highest level, in response to the spread of the disease that has infected more than 600 people in the country, mostly in the last few days. The step was last taken in 2009 to guard against a novel influenza outbreak that killed more than 260 people in South Korea. Under the highest alert level, authorities can order the temporary closure of schools and reduce the operation of public transportation and flights to and from South Korea.

Moon's education minister, Yoo Eun-hae, said later Sunday that the new school year for kindergartens, elementary, middle and high schools in South Korea has been put off by one week and will start on March 9.

Moon said the outbreak “has reached a crucial watershed,” and that the next few days will be critical. “We shouldn't be bound by regulations and hesitate to take unprecedented, powerful measures,” he said.

South Korea announced 169 more cases of the new virus, bringing the country's total to 602. It also reported three more fatalities, raising its death toll to six.

Mainland China reported 648 new infections for a total of 76,936. The daily death toll fell slightly to 97. In all, 2,442 people have died in the country from COVID-19, the disease caused by the virus.

The number of new Chinese cases has seesawed daily but has remained under 1,000 for the past four days. Several changes to how infections are counted, however, have made it difficult to draw conclusions from the figures.

The central Chinese city of Wuhan and other parts of Hubei province, where the outbreak first emerged in December, remain under lockdown. More than 80% of the country's cases are in Hubei, where the death toll has also been higher than the rest of the nation.

Most of the South Korean cases have been reported in the country's fourth-largest city, Daegu, and the surrounding area. According to the Korea Centers for Disease Control and Prevention, some 320 cases have also been confirmed to have links to a branch of the local Shincheonji church in Daegu, which has become the biggest cluster of viral infections in South Korea.

Shincheonji, which has been viewed as a cult movement by mainstream Christian organizations, tried to defend itself from growing public anger directed at the church.

In a video statement posted on its website, church spokesman Simon Kim said Shincheonji has shut down all its 1,100 local churches and other facilities since one of its church members tested positive for the virus on Feb. 18, the first patient in Daegu.

Earlier Sunday, Daegu Mayor Kwon Yong-jin said there were concerns that the number of those infected in the city could see yet another massive increase because authorities were launching intensive examinations of church members with virus-related symptoms.

Meanwhile. a cruise ship passenger who had been hospitalized after testing positive for the new virus died on Sunday, the third fatality from the Diamond Princess, Japan's health ministry said.

The ministry also announced 57 more cases of infections from the ship, including 55 crew members still on board and two passengers who had infected roommates and are in a prolonged quarantine at a government facility.

With the new cases, 691 people have been infected on the ship, or nearly one-fifth of its 3,711 passengers and crew. Japan has confirmed a total of 838 cases and four deaths from the virus, including those on the ship.

Meanwhile, a diplomatic row erupted after Israel turned back a South Korean airliner, underscoring fear and tensions over the fast-spreading outbreak.

A Korean Air flight with 188 passengers that landed at Tel Aviv's Ben Gurion airport Saturday evening was taxied away from the terminal while authorities allowed only 11 Israelis to enter the country. The plane returned to South Korea with the rest of the passengers on Sunday, according to airline officials.

Seoul's Foreign Ministry said Sunday that it was closely monitoring the incident and providing active consular assistance to South Koreans staying in Israel. It said it will evacuate South Korean tourists from Israel if necessary.

Yonhap news agency cited South Korea's Foreign Ministry as registering a strong protest with the Israeli government.

South Korea earlier informed Israel that a group of tourists who travelled to Israel and the West Bank for a week this month tested positive for the virus upon returning home. Israeli and Palestinian health authorities asked people who were in close contact with the tourists to quarantine themselves.

South Korean health authorities said Sunday that 18 of the 39 South Koreans who had made the group pilgrimage later tested positive for the virus. She said the 21 others were being tested. Forty-one Catholic churches in their neighbourhoods halted Sunday Masses and other gatherings.

Israel's Foreign Ministry issued travel warnings to South Korea and Japan due to the coronavirus, and the Health Ministry ordered Israelis returning from those countries to remain in home quarantine, as previously ordered for those returning from Hong Kong, China, Macau, Thailand and Singapore.

Israeli Prime Minister Benjamin Netanyahu will be adding more restrictions on entry to Israel from additional countries, including Australia and Italy.

Jordan said it was denying entry of non-Jordanians coming from Iran and South Korea, on top of a previous ban on those coming from China. Nationals arriving from those countries will be quarantined.

Downtown Daegu was mostly deserted Sunday, with shelves at some supermarkets and stores empty. Many restaurants, bars, real-estate offices and tour agencies shut down as traffic nosedived and people stayed home, ordering food and supplies online.

Kim Mi-yeon, who opened her cake shop in Daegu on Sunday despite worries about infection, said she received only one group of customers.

“I'm also worried about being infected, but I still opened my shop today to make a living,” she said by phone. “On weekends, I used to hire five part-time employees, but I've recently told all of them not to come. How can I hire them at a time when I have fewer then 10 customers a day?”

Associated Press journalists Yanan Wang and Henry Hou in Beijing, Frances D'Emilio in Rome, Ilan Ben Zion in Jerusalem, Fares Akram in Amman, Jordan, and Mari Yamaguchi in Tokyo contributed to this report.