Health experts sounded the alarm Friday over the worldwide threat of the coronavirus, with officials warning of its "likely" community spread in the United States and the World Health Organization cautioning that "the window of opportunity is narrowing" for containing the outbreak worldwide.

The COVID-19 coronavirus, which erupted in China in December, has killed at least 2,360 people and sickened at least 77,900 worldwide, the majority of cases in mainland China.

Dr. Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Diseases, told reporters Friday that U.S. health officials are preparing for the coronavirus to become a pandemic.

“We’re not seeing community spread here in the United States, yet, but it’s very possible, even likely, that it may eventually happen,” she said. “Our goal continues to be slowing the introduction of the virus into the U.S. This buys us more time to prepare communities for more cases and possibly sustained spread.”

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She said the CDC is working with state and local health departments “to ready our public health workforce to respond to local cases.” These measures include collaboration with supply chain partners, hospitals, pharmacies and manufacturers to determine what medical supplies are needed.

She said the “day may come” here where we have to shut down schools and businesses like China has done.

Meanwhile in Geneva, the director-general of the World Health Organization, alarmed by the recent spread of the coronavirus from Iran, warned Friday that while the chance to contain the virus globally still exists, "the window of opportunity is narrowing."

"We still have a chance to contain it, but we have to prepare for other eventualities," said Tedros Adhanom Ghebreyesus. "This could go in many directions, it could be even messy. It is in our hands now ... we can reverse or avert serious crisis. If we don't, if we squander this opportunity, then there could be a serious problem on our hands."

Among other measures, Tedros called for financial aid to help countries fighting the virus to buy critical medical equipment and to strengthen their health systems.

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The world community, he said, has a "fighting chance" to contain the spread of the virus, but we "must not look back and regret that we failed to take advantage of the window of opportunity that we have now."

Tedros, speaking to reporters in Geneva, said the new cases in Iran show how the virus, which originated in Wuhan, China, is now moving not only to second countries, but to third countries in a lengthening chain of transmission.

“The cases that we see in the rest of the world, although the numbers are small, but not linked to Wuhan or China, it’s very worrisome,” Tedros said. “These dots are actually very concerning.”

The Global Health Security Index, which was issued last year, found that only 13 of nearly 200 countries score in the top tier, suggesting that most of the world would struggle to deal with a major outbreak of a deadly infectious disease such as Ebola.

The index is a project of the Nuclear Threat Initiative (NTI) and the Johns Hopkins University Center for Health Security, with research by The Economist Intelligence Unit.

35 cases of coronavirus in the US

The CDC reported that at least 35 people in the United States are infected with the virus. Of those, 14 were travelers who fell ill after returning from a trip abroad, while 21 were were people “repatriated” by the State Department.

Messonnier, of the CDC, said more infections are expected from among passengers on the Diamond Princess cruise ship and are in quarantine.

She said they are “they are considered at high risk for infection” because they may have come in contact with infected pesons on the ship.

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5 deaths in Iran

Iranian health authorities on Saturday reported a fifth death from the new virus that emerged in China, and said the fatality was from among 10 new confirmed cases of the virus in Iran.

So far, 28 cases have been confirmed in Iran, including the five who died. People are being treated for the virus in at least four different cities, including the capital, Tehran, where some pharmacies had already run out of masks and hand sanitizer. Other cities are Qom, Arak and Rasht.

Health ministry spokesman Kianoush Jahanpour made Saturday's announcement for the latest figures on state TV, but did not specify when the fifth death occurred. Two people had died earlier Friday from COVID-19, the illness caused by virus. Authorities reported two deaths previously this week.

Jahanpour said that of the 10 newly detected cases, two were in the capital of Tehran and eight were in the city of Qom. That's where the first two elderly patients died on Wednesday. He said the two patients in the capital had visited Qom or had links with the city.

Minoo Mohraz, an Iranian health ministry official, previously said the virus “possibly came from Chinese workers who work in Qom and traveled to China.” She did not elaborate. A Chinese company has been building a solar power plant in Qom.

Elsewhere in the region, Saudi Arabia announced that citizens and residents of the kingdom are not permitted to travel to Iran following the spread of the virus there. Anyone previously in Iran will only be permitted entry to the country after the 14-day incubation period of the virus has passed.

At the same time, Lebanon announced Friday its first confirmed coronavirus case in the country from an individual who had apparently picked up the virus during a visit to Qom, according to Lebanese Health Minister Hammad Hassan said during a news conference Friday.

In Canada, a woman in her 30s was diagnosed with a mild case of the virus after a trip to Iran, prompting authorities to notify those who traveled with her on the same aircraft, according to health officials in British Columbia.

2nd death in Italy; 10 northern towns on lockdown

Schools, businesses and restaurant were closed in nearly a dozen northern Italian towns Saturday following reports of two deaths in the region tied to the virus.

A female resident in the Lombardy region died only hours after a 77-year-old man succumbed near Padua, in the Veneto region, the ANSA news agency reported.

Local authorities in Lombardy and Veneto ordered the lockdown, including the cancellation of sporting events, while the mayor of Milan, the business capital of Italy, shuttered public offices. In Veneto, civil protection crews set up a tent camp outside a closed hospital, where several confirmed cases were being held in isolation, to screen medical staff for the virus.

In hard-hit Codogno, where the first patient in the north to fall ill was in critical condition, the main street was practically a ghost town Saturday. The few people out on the streets were wearing coveted face masks, which were nearly impossible to find in sold-out pharmacies.

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China's leaders say nation yet to turn corner in virus fight

As China once again shifts it methodology for counting coronavirus cases, China's top leadership on Friday cautioned that the country had not yet turned the corner on halting the spread of the virus that has killed more than 2,200 people.

“We should clearly see that the turning point of the development of the epidemic across the country hasn’t arrived yet,” the Communist Party’s Politburo Standing Committee said at a meeting led by President Xi Jinping and reported by state broadcaster CCTV.

The 25-member Politburo, made up of the senior officials of the ruling Communist Party, said the situation in Hubei province and its capital, Wuhan, where the outbreak erupted in December, remains grave.

The latest warning followed several days of official reports indicating a downward trend in newly reported cases. The data, however, has been muddied by another change in how the country's health authorities count cases.

China last week began recording cases without waiting for lab results, which caused a big spike in cases. On Thursday, health officials returned to counting only lab-confirmed positive cases, discounting some cases where lab tests came back negative.

The National Heath Commission earlier reported almost 900 newly confirmed cases in the previous 24 hours, with the death toll rising by 118.

The 25-member body said the outbreak has been “preliminarily contained” and urged party committees and governments at all levels to carry out prevention and control work without any relaxation to “win the people’s war against the epidemic.”

In the latest cause for alarm, officials in Hubei Province, the epicenter of the outbreak since December, more than 500 cases were diagnosed in prisons, Justice Ministry official He Ping told reporters at a daily briefing.

Seoul bans rallies, curbs church meetings over virus scare

The Seoul city government on Friday said it will ban rallies at three major public squares in the city center and close down churches operated by the Shincheonji religious movement in a bid to thwart any spread of the coronavirus in South Korea.

Seoul Mayor Park Won-soon said the aim was "to protect the elderly who are susceptible to contagious diseases," according to the Yonghap news agency. Violators could be fined up to the equivalent of $2,500.

Prime Minister Chung Sye-kyun, declaring the country in an "emergency phase," said in a televised statement the central government will concentrate its support to the southeastern region to ease a shortage in sickbeds, medical personnel and equipment.

South Korea, which has reported 204 cases, recorded its second virus-related death Friday. Many of the cases have been clustered around Daegu, a southeastern city, raising fears that the outbreak is getting out of control.

Most of the new cases there are linked to the Shincheonji church, which claims about 200,000 followers in South Korea. It said it has closed all of its 74 sanctuaries around the nation and told followers to instead watch its worship services on YouTube.

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Villagers in Ukraine block roads in virus protest

Some residents in Ukraine's Poltava region blocked roads, burned tires and threw stones at buses because of the state's plan to house more than 70 evacuees from China in a sanatorium in the village of Novi Sanzhary, according to local media reports. The 45 Ukrainians and 27 foreign evacuees had been airlifted from Wuhan.

Nine police officers and one civilian were hospitalized as a result of Thursday's turmoil, and 24 protesters were detained.

In a bid to reassure local residents, Ukrainian Health Minister Zoryana Skaletska voluntarily joined the evacuees for their 14-day quarantine.

The incident coincided with the circulation of a phony email that Ukrainian intelligence officials said originated outside the country, the Washington Post reported. The fraudulent missive claimed there were five cases of coronavirus in the county, although only two Ukrainians, who had been in a cruise ship, have been infected and both recovered while in quarantine.

Contributing: Associated Press