The first death from the novel coronavirus has been confirmed on US soil, in Washington state, health officials said Saturday, after the first four cases of unknown origin were detected, indicating the disease was spreading in the country.

The fatality occurred in King county, the most populous in the state and home to Seattle, a city of more than 700,000 people. The victim was a woman in late 50s.

US President Donald Trump said he would address the media about the "latest coronavirus developments" at 1:30 pm Eastern time (1830 GMT).