BEIJING — China moved to lock down at least three cities with a combined population of more than 18 million in an unprecedented effort to contain the deadly new virus that has sickened hundreds of people and spread to other parts of the world during the busy Lunar New Year holiday.

The train station and airport in Wuhan, the epicenter of the outbreak, were shut down, and ferry, subway and bus service was halted. Normally bustling streets, shopping malls, restaurants and other public spaces in the city of 11 million were eerily quiet. Police checked all incoming vehicles but did not close off the roads.

Similar measures were being imposed Friday in the nearby cities of Huanggang and Ezhou. In Huanggang, theaters, internet cafes and other entertainment centers were also ordered closed.

In the capital, Beijing, major events were canceled indefinitely, including traditional temple fairs that are a staple of holiday celebrations, to stop the spread of the virus. The Forbidden City, the palace complex in Beijing that is now a museum, is closed indefinitely.

China’s National Health Commission said Friday morning the confirmed cases of the new coronavirus had risen to 830 with 25 deaths. The first death was also confirmed outside the central province of Hubei, where the capital, Wuhan, has been the epicenter of the outbreak. The health commission in Hebei, a northern province bordering Beijing, said an 80-year-old man died after returning from a two-month stay in Wuhan to see relatives.

Other cases have been confirmed in the United States, Japan, Taiwan, South Korea and Thailand. Singapore and Vietnam reported their first cases Thursday, and cases have also been confirmed in the Chinese territories of Hong Kong and Macao.

Many countries are screening travelers from China for symptoms of the virus, which can cause fever, coughing, breathing difficulties and pneumonia.