British health authorities on Sunday confirmed 12 more cases of the new coronavirus, bringing the country's overall tally to 35, and the Czech Republic announced its first three infections.

The British government's chief medical officer, Prof. Chris Whitty, said one of the new patients "had no relevant travel and it is not yet clear whether they contracted it directly or indirectly from an individual who had recently returned from abroad."

Whitty said medical workers were still investigating the cause of that infection.

Three of the new COVID-19 patients in Britain were contacts of an existing patient while six infected people had recently traveled from Italy and two had arrived from Iran. Both countries have been hard hit by the coronavirus that emerged late last year in central China, with Italy seeing over 1,100 cases and 29 deaths, the most in Europe.

Elsewhere in Europe, Czech Health Minister Adam Vojtech said Sunday that two COVID-19 patients were hospitalized in Prague and one was hospitalized in northern city of Usti nad Labem. All three had some travel ties to northern Italy.

A new U.S. government advisory on Sunday urged Americans not to travel to two Italian regions hardest hit by a new virus, raising the level of warning for the Lombard and Veneto regions to the highest level.

The spreading coronavirus epidemic shut down France's Louvre Museum on Sunday, with workers who guard its famous trove of artworks fearful of being contaminated by the museum's flow of tourists from around the world. Almost three-quarters of the Louvre's 9.6 million visitors last year came from abroad.

Spain said Sunday the country now has 71 virus cases. The eastern Valencia region has the most, all linked to Italy, including soccer fans who had travelled to Milan for a match in early February.

The Dutch health minister also announced three new cases, bringing the Netherlands' overall tally of patients to 10.