China’s health minister has warned that the coronavirus’ ability to spread “seems to be getting stronger” as the US plans to evacuate its citizens from Wuhan. 

Fifty-six people are now known to have been killed by the outbreak, which has accelerated in China and seen the lockdown of a number of major cities and attractions. 

Chinese president Xi Jinping called the outbreak a “grave situation” on Saturday, and the government stepped up efforts to restrict travel and public gatherings while rushing medical staff and supplies to Wuhan, the epicentre of the outbreak, which remains on lockdown.

The US consulate in Wuhan announced on Sunday plans to evacuate its personnel and some private citizens aboard a charter flight.

Speaking to Sky News’ Sophy Ridge, home secretary Priti Patel said the UK government was “looking at all the options” to help Britons leave Wuhan.

“It is right that we look at all options and that’s exactly what the government is doing right now,” she said. 

Her comments follow reports that foreign secretary Dominic Raab has ordered officials to examine the logistics for an airlift from the city. 

The latest figures reported from China on Sunday morning cover the previous 24 hours and mark an increase of 15 deaths and 688 cases for a total of 1,975 infections.

Cases have also been found in Thailand, Japan, South Korea, the US, Vietnam, Singapore, Malaysia, Nepal, France, Australia and Canada.

National Health Commission minister Ma Xiaowei, speaking at a press briefing, said knowledge of the virus was limited, adding that the “virus’s ability to spread seems to be getting stronger.”  

He said incubation period for the coronavirus can range from one to 14 days, and that the virus is infectious during incubation, which was not the case with SARS, a coronavirus that originated in China and killed nearly 800 people globally in 2002 and 2003.

Containment efforts, which have thus far included transportation and travel curbs and the cancellation of big events, will be intensified.

A notice from the US embassy in Beijing said there would be limited capacity to transport US citizens on the Tuesday flight from Wuhan that will go directly to San Francisco.

It said in the event there are not enough seats, priority will be given to to individuals “at greater risk from coronavirus”.

French car maker PSA Group said it will evacuate its employees from Wuhan, quarantine them and then bring them to France.

France’s foreign ministry said it was working on “eventual options” to evacuate French citizens from Wuhan “who want to leave”.

Also on Sunday, two of Hong Kong’s biggest attractions, Hong Kong Disneyland and Ocean Park, announced they were closing for an unspecified period. 

Travel agencies have been told to halt all group tours and concern is growing over the potential impact of millions of people travelling back to cities after China’s Lunar New Year holiday ends on Thursday.

In the heart of the outbreak where 11m residents are already on lockdown, Wuhan banned most vehicle use, including private cars, in downtown areas starting on Sunday.

Images from the metropolis showed the usually-bustling streets eerily quiet as residents stayed at home in a bid to avoid infection.

Officials have said the city will assign 6,000 taxis to neighbourhoods to help people get around if they need to.

Wuhan plans to build a second makeshift hospital with about 1,000 beds to handle the growing number of patients.

The city said another hospital was expected to be completed by February 3.

Medical workers have been among those infected and Wuhan media reported a doctor died of the virus on Saturday. The 62-year-old worked at the ear, nose and throat department at Hubei Xinhua hospital.

Medical supplies are reportedly being rushed to the city, including 14,000 protective suits, 110,000 pairs of gloves, masks and goggles.

The National Health Commission said it is bringing in medical teams to help handle the outbreak, a day after videos circulating online showed throngs of frantic people in masks lined up for examinations and complaints that people were turned away at hospitals that were at capacity.

The new virus comes from a large family of what are known as coronaviruses, some causing nothing worse than a cold.

It causes cold- and flu-like symptoms, including cough and fever, and in more severe cases, shortness of breath. It can worsen to pneumonia, which can be fatal.

Those killed by the virus have mostly been middle-aged or elderly people, sometimes suffering from other conditions that weaken their ability to fight back.

Around China, authorities cancelled a host of Lunar New Year events, and closed major tourist destinations and cinemas.

Beijing’s Forbidden City and Shanghai Disneyland closed and people cancelled restaurant reservations before the holiday, normally a time of family reunions, sightseeing trips and other festivities in the country of 1.4 billion people.

In Beijing and other cities, most people wore medical masks on buses and the subway or to public places such as grocery stores, where workers dispensed hand sanitiser to customers.

Some parts of the country had checkpoints for temperature readings and made masks mandatory.