HONG KONG - SOME secondary schools in Hong Kong have reported suspected flu outbreaks, and four have closed voluntarily as of yesterday, Education Bureau spokesman Connie Lin said.

Primary schools and kindergartens remained closed yesterday as a precaution, keeping more than half a million students at home.

The government ordered the two-week closure of all primary schools and kindergartens starting on Thursday, a week before the start of the Easter holidays.

It was the first such public health measure since the outbreak of severe acute respiratory syndrome, or Sars, more than five years ago.The government revealed on Thursday that two more children, a seven-year-old and an eight-year-old, were hospitalised with flu-related complications, but their conditions were stable. Three others have died after suffering flu-like symptoms.

In statistics released late on Thursday, Hong Kong reported 18 confirmed outbreaks, 106 suspected ones and 837 affected people in the city of nearly seven million since March 6.

Most of the cases have been confined to schools.

Sars surfaced in southern China in November 2002 before spreading to Hong Kong, where it killed 299 people and sparked a major public panic in Hong Kong and other cities.

South China Morning Post reported yesterday that the dark shadow cast by the Sars epidemic in 2003 was behind the government's decision to close all primary schools and kindergartens.

'The shadow left by Sars is still fresh,' the source said.

'So we decided, 'Why don't we take a more cautious and immediate approach by shutting down the classes if we find the virus has more serious effects on children than on adults?'

In 2003, the government was accused of underestimating the seriousness of the Sars outbreak, which eventually forced health chief Yeoh Eng Kiong to resign.

Sources said Health Secretary York Chow sought the support of Chief Executive Donald Tsang and Chief Secretary Henry Tang at about 9pm on Wednesday, shortly after an expert committee set up to investigate the recent deaths suggested a suspension.

The decision was announced shortly before 10.30pm on Wednesday.

Dr Chow apologised to those affected.

'It is a difficult decision which put huge political pressure on me,' he was quoted as saying by the Post.

Hong Kong is also on its guard against bird flu, which killed six people here in 1997.

Scientists also fear the virus that causes it could eventually mutate into a form that spreads easily among humans.

Hong Kong occasionally finds wild birds with avian influenza, the latest being a peregrine falcon. After several tests, scientists confirmed that it had contracted the deadly H5N1 strain, the government said in a statement yesterday.

ASSOCIATED PRESS