Lieutenant Mark Boyd of the Seventh Fleet told local radio that US Pacific Command was only allowing port calls that were "mission-essential".

Lieutenant Boyd refused to comment further on the cancellation or specify when the travel restrictions came into effect.

The US Consulate General in Hong Kong said it could not comment as it did not know if the directive was official.

It was also reported the USS Carl Vinson had cancelled a port call here last week, citing operation requirements and not the outbreak of a killer strain of atypical pneumonia called Severe Acute Respiratory Syndrome (SARS).

However, US consulate spokeswoman Susan Stevenson could not confirm whether the port call of the aircraft carrier had been cancelled.

But she said the US Navy had "deferred all port calls to Hong Kong until restrictions were lifted".

SARS has killed 17 and infected some 734 people in Hong Kong.

Since February, the former British colony has been at the centre of the SARS epidemic that has spread to 22 different countries, infecting about 2,400 people and causing 81 deaths.

SPACE.WIRE