Hurricane Ophelia strengthened to a Category 3 storm as it passed near the Portuguese Azores archipelago on Saturday en route for Ireland.

"We have informed the American hurricane center that Ophelia has become Category 3, but that doesn't change our levels of alert," said Elsa Vieira, from the Portuguese Meteorological Institute's (IPMA) regional service.

Ophelia. packing winds in excess of 100 kilometres per hour, was set to pass 150 kilometres (93 miles) south of the Azores island of Santa Maria at around 1800 GMT without making landfall, she told AFP.

The storm, which has strengthened to Category 3 on a five category scale, is then expected to head northwest towards Ireland.

Philip Klotzbach, a hurricane specialist at Colorado State University, said Ophelia was "now a major hurricane" and was travelling the farthest east of any Atlantic hurricane on record.

The Miami-based US National Hurricane Center said Friday that Ophelia was forecast to produce total rain accumulations of two to four inches (51 to 101 millimetres) over the southeastern Azores through Saturday.

The rainfall could trigger flooding, it warned.

Seven of the nine islands that make up the Azores were placed on red alert by the regional civil protection services between 1800 GMT and 2400 GMT due to expected rainfall of 40 millimetres per hour.

The local population, which totals 245,000, was told to stay home if possible during the passage of the hurricane which is now a category two out of five, but still capable of generating winds of more than 100 kilometres (60 miles) per hour.

All 17 firefighting units on the archipelago are on standby to intervene, a spokeswoman for the security services told AFP.

The authorities imposed traffic restrictions on the islands of Sao Miguel and Santa Maria, which are expected to see the worst of the hurricane.

- Reaching Ireland -

Ophelia should no longer be a hurricane by the time it reaches Ireland, but will still whip up a powerful storm, the US hurricane centre predicted.

Five counties in the west of Ireland will be placed on red alert for "severe" weather conditions from Monday morning to early Tuesday, the Irish Meteorological Service said.

People in those counties are advised "to take action to protect themselves" and their property.

Mean wind speeds in excess of 80 km per hour and gusts in excess of 130 km per hour are expected, potentially causing structural damage and disruption, with dangerous marine conditions due to high seas and potential flooding, the service said.

Parts of the UK, meanwhile, have been placed on yellow alert for Monday and Tuesday, the lowest warning level triggered by "serious" weather conditions.

Source: AFP