U.S. President Donald Trump has offered China any help needed to combat a deadly outbreak of a coronavirus that has killed 81 people.

In a Monday tweet, Trump said, "We are in very close communication with China concerning the virus," adding, "We have offered China and President Xi (Jinping) any help that is necessary. Our experts are extraordinary!"

Chinese Premier Li Keqiang visited the city of Wuhan on Monday to meet with health officials and examine the response to the outbreak. Wuhan is the center of the outbreak and people there and in several other cities face strict restrictions on movement as the government tries to prevent the virus from spreading.

The head of the World Health Organization, Dr. Tedros Ghebreyesus, arrived Monday in Beijing, where he is expected to meet senior Chinese officials to discuss the outbreak. The agency said there is still a chance to get ahead of the virus if there is strong cooperation.

Chinese Premier Li Keqiang, wearing a mask and protective suit, speaks to medical workers as he visits the Jinyintan hospital where the patients of the new coronavirus are being treated, in Wuhan, Hubei province, China, Jan. 27, 2020.

Beijing authorities also reported the capital's first death from the virus.

Separately, in an effort to stop the virus from spreading, Mongolia closed its vast border with China, while Hong Kong and Malaysia announced they would ban entry to visitors from Wuhan.

Global stock markets plunged Monday as investors feared the economic impact from the coronavirus.

Chinese officials took an extra step Sunday to extend the Lunar New Year holiday three extra days to cut down on group gatherings.

Global spread

The latest figures reported by Chinese health officials include more than 2,700 cases of people being sickened by the virus.

Cases have also been reported in Australia, Canada, France, Hong Kong, Japan, Macao, Malaysia, Nepal, Portugal, Singapore, South Korea, Taiwan, Thailand, the United States and Vietnam. The World Health Organization says most of those are people had a travel history in Wuhan, with several others having contact with someone who traveled there.

People queue up to purchase face masks outside a shop in Hong Kong, Jan. 27, 2020.

There have been no reported deaths linked to the virus outside of China.

The head of the U.S. Centers for Disease Control and Prevention's respiratory disease office, Nancy Messonnier, said Sunday there were five confirmed cases in the United States, and that all five people had direct contact with others in Wuhan.

The patients are isolated in hospitals as doctors and health officials try to learn more about the virus. The CDC says it is investigating about 100 suspected cases in 26 states.

Chinese National Health Commission Minister Ma Xiaowei said Sunday little is known about the virus. But doctors do know it has an incubation period that can range from one to 14 days. Ma said the virus is infectious during the incubation period, when no signs or symptoms of the disease are present.

'Grave situation'

President Xi Jinping said China is facing a "grave situation" and experts and other resources would be concentrated at specific hospitals to treat severe cases.

The virus is believed to have emerged late last year at a Wuhan seafood market illegally selling wildlife. Chinese authorities have imposed a temporary ban on the selling of wildlife. Wuhan is the capital of China's Hubei province.

Paramilitary police wear face masks as they stand guard at Tiananmen Gate adjacent to Tiananmen Square in Beijing, Jan. 27, 2020.

The virus hit China just as it was beginning celebrations to mark the Lunar New Year, resulting in the canceling or the scaling back of festivities for tens of millions of Chinese.

Tourist destinations are closed and school closings have been extended in an effort to stop the spread of the virus. Public transportation has been severely restricted. Many businesses have closed or asked employees to work from home.

The WHO recommends several steps to help protect people against acute respiratory infections. They include avoiding close contact with those already infected, frequent hand-washing, and avoiding unprotected contact with farm animals and wild animals.

VOA's Margaret Besheer contributed to this report.

