Mayor of Washington D.C. Muriel Bowser said a Nigerian who passed through the US capital city has tested positive for coronavirus in neighbouring state of Maryland.

She announced this at a news conference on Saturday night.

She said the Nigerian had visited Washington D.C. and tested positive later in Maryland. All his contacts are being traced in the city.

Bowser had earlier announced that a man in his 50s has tested positive for coronavirus, marking the first presumptively confirmed case in the capital.

She said the man started exhibiting symptoms of COVID-19 in late February and was hospitalized Thursday.

President Donald Trump says he isn’t concerned “at all” about the coronavirus getting closer to the White House after the first Washington case and an attendee of a recent political conference where Trump himself had spoken also tested positive for the virus.

Nineteen people have died in the U.S. from the virus. The number of infections in the U.S. is now above 400.