This photo taken on February 12, 2017 shows an H7N9 bird flu patient being treated in a hospital in Wuhan, central China's Hubei province. A number of provinces in China have stepped up efforts to prevent H7N9 avian flu following reports of scattered human cases of the virus, state media reported. / AFP PHOTO / STR / China OUT

It is marked the first casualty of a US citizen by coronavirus.

The 60-year-old retiree who was diagnosed with coronavirus died at Wuhan’s Jinuintan Hospital, the city where the deadly virus broke out, on Thursday.

The news of his death came today from a spokesman for the US Embassy in Beijing.

Chinese authorities reported that Friday was the highest number of casualties for 24 hours in China, with 86 dead.

So far, the total number of victims of coronavirus has reached 722, while 34,546 people have been confirmed affected.

The highest number of deaths and those affected by coronavirus have been recorded in Wuhan City and Hubei Province, a region of about 60 million people, which has been isolated for several weeks after the deadly outbreak.

China has isolated Wuhan city and Hubei province, blocking transportation and barring people from leaving.

Specialist doctors have been sent to Wuhan and Hubei to try to determine if sick patients have been infected with coronavirus or any common illness.