Mainland state broadcaster CCTV says a group of medical experts arrived in the city of Wuhan on Tuesday morning to investigate a suspected outbreak of Severe Acute Respiratory Syndrome (Sars).

Twenty-seven suspected cases have been reported.

The Wuhan Municipal Health Commission said a number of clinics and hospitals in the city have reported patients with pneumonia and the cause is unknown.

The patients have immediately been isolated, the commission said. Those infected are all believed to have visited a seafood market in the city.

The commission said it was closely monitoring the patients’ situation.

Some mainland media have also quoted sources from Shanghai’s Tongji University as saying the new cases of pneumonia and the Sars virus appear to be very similar, with both belonging to the coronavirus category.

The Sars epidemic in 2003 infected more than 1,700 people in Hong Kong and killed almost 300.

The disease, which is from the same family of viruses as the common cold, emerged in Guangdong province at the end of 2002. It spread to more than 30 countries infecting over 8,000 people, with 744 deaths in total.