Hong Kong was in a state of panic on Tuesday over the new deadly strain of pneumonia, which has killed 63 people and infected almost 1,900 around the world, after a hoax on a website prompted frantic buying in supermarkets.

Thousands of people stripped shelves clean of rice, toilet paper and cooking oil after a teenager set up a dummy website that looked like the internet version of Ming Pao, a local Chinese daily, and declared that Hong Kong had been declared "an infected area".

Government officials called a press conference to quell panic buying and crush rumours that Hong Kong's airport had been closed.

Margaret Chan, a senior health official in the local government, said Hong Kong had "no plan and no need" to declare the city an infected area. She said the city, where 685 people have become ill, maintained "a regular food supply" and that its airport and other transport networks were operating normally.

The government said on Tuesday that 84 patients had been discharged since the epidemic began, a sign that local hospitals' treatment of a cocktail of anti-viral drugs and steroids to modulate the extreme response by the patient's immune system to the virus is working.

Separately, the first suspected cases of Severe Acute Respiratory Syndrome (Sars) were reported in Malaysia and Indonesia on Tuesday, while German health authorities said a 72-year-old man was the first citizen confirmed to have contracted the illness.

The World Health Organisation said outbreaks in most parts of the world - such as Vietnam, Singapore and Canada - were under control. But the illness was still spreading in Hong Kong and in China, after the original outbreak in Guangdong province last November.

David Heymann, WHO's head of communicable diseases, said WHO was considering whether to issue advice on whether to travel to affected areas and what precautions to take, but for the moment was sticking simply to its earlier recommendation that passengers from those areas be screened to prevent the international spread of the disease.

In the light of Hong Kong's experience, the WHO was investigating whether the disease could be spread by an environmental vector such as water or sewage. But officials said WHO was confident that the primary mode of transmission was person-to-person and that the disease was not being spread through air circulation systems.

Meanwhile, a Chinese foreign ministry spokesman yesterday denied there had been a cover-up over the extent and origins of the outbreak. Beijing has been criticised for not providing adequate information to international health authorities about the spread of the illness in Guangdong.

On Tuesday a spokesman said the government had taken a "responsible and scientific attitude" and said the mainland had taken adequate steps to bring the illness under control. Additional reporting by Frances Williams in Geneva