The Diamond Princess is seen in Yokohama near Tokyo on Monday.
The Diamond Princess is seen in Yokohama near Tokyo on Monday. Kyodo

An official from the US Centers for Disease Control and Prevention is in Tokyo to assist the US Embassy with its support of Americans on board the Diamond Princess, CNN has learned.

Passengers have been stuck on the cruise ship since February 4, after reports emerged that one of its passengers was infected with the coronavirus that has swept through China.

Since then, 135 people have been confirmed infected, including at least 24 Americans.

“We believe the Japanese authorities and cruise lines are working hard to keep all passengers – and the public – safe,” a State Department official told CNN.

“We ask passengers on board for their patience and understanding and to fully cooperate with and follow the instructions of global medical authorities and the Japanese government.”

Over the weekend, the CDC sent a letter to Americans on board the Diamond Princess advising them of hygiene procedures. “Remaining in your room on the ship is the safest option to minimize your risk of infection,” the letter said.

Consular officers are also visiting American cruise ship passengers who have been sent to hospitals in Tokyo.