BEIJING - New virus cases in China continued to fall Wednesday, with 1,749 new infections and 136 new deaths announced after China's leader said disease prevention and control was at “a critical time.”

The much-criticized quarantine of a cruise ship in Japan to avoid spreading the virus ends later in the day. The 542 cases on the ship were the most in any place outside of China and medical experts have called the quarantine a failure.

The updated figures on the COVID-19 illness for mainland China bring the total for cases to 74,185 and deaths to 2,004. New cases have fallen to under 2,000 daily for the past two days.

Chinese President Xi Jinping spoke about the efforts to control the outbreak in a phone call with British Prime Minister Boris Johnson described in state media.

Separately, the U.N. secretary-general told The Associated Press that the virus outbreak “is not out of control but it is a very dangerous situation.” Antonio Guterres said in an interview in Lahore, Pakistan, that “the risks are enormous and we need to be prepared worldwide for that.”

China has locked down several cities in central Hubei province where the outbreak hit hardest, halting nearly all transportation and movement except for the quarantine efforts, medical care and delivery of food and basic necessities.

China also may postpone its biggest political meeting of the year, the annual congress due to start in March, to avoid having people travel to Beijing while the virus is still spreading. One of the automotive industry's biggest events, China's biannual auto show, was postponed, and many sports and entertainment events have been delayed or cancelled.

Many countries set up border screenings and airlines cancelled flights to and from China to prevent further spread of the disease, which has been detected in around two dozen countries and caused almost 1,000 confirmed cases outside mainland China. Five deaths have been reported outside the mainland, in Hong Kong, Taiwan, Japan, the Philippines and France.

The largest number of cases outside China is the 542 on the Diamond Princess at a port near Tokyo.

South Korea evacuated six South Koreans and a Japanese family member from the ship, and they began an additional 14-day quarantine Wednesday. More than 300 American passengers were evacuated earlier and are quarantined in the United States, including at least 14 who had tested positive for the virus.

On Tuesday, the U.S. government said the more than 100 American passengers who stayed on the ship or were hospitalized in Japan would have to wait for another two weeks before they could return to the U.S.

The U.S. also upgraded its travel advisory for China to Level 4, telling its citizens not to travel to anywhere in the country and advising those currently in China to attempt to depart by commercial means.

“In the event thatthe situation further deteriorates, the ability of the U.S. Embassy and Consulatesto provide assistance to U.S. nationals within China may be limited. The United States is not offering chartered evacuation flights from China,” the notice said.

“We strongly urge U.S. citizens remaining in China to stay home as much as possible and limit contact with others, including large gatherings. Consider stocking up on food and other supplies to limit movement outside the home,” the notice said. The U.S. previously flew out scores of its citizens on charter flights from Wuhan but does not have any further plans to do so, it said.

Despite, such warnings, the capital Beijing was showing signs of coming back to life this week, with road traffic at around a quarter of usual up from virtually nothing a week ago. While most restaurants, stores and office buildings remained closed, others had reopened. People entering were required to have their temperatures taken and register their contact information.