MIAMI, Sept 3: Thousands of people choked Florida's main highways on Friday after 2.5 million people were told to leave their homes - the largest evacuation in state history, as Hurricane Frances, after pummeling the Bahamas, barrelled toward the eastern US coast.

"We need to take this seriously, this is a deadly storm" said Florida Governor Jeb Bush, urging residents in threatened areas to board up their homes and seek shelter inland.

Most of Florida's densely populated east coast was placed under a hurricane warning, which means the storm could slam within 24 hours into the state that is still recovering from the devastation of Hurricane Charley last month.

About 2.5 million people along south Florida's Atlantic coast were told to evacuate their homes and move to safer areas as Frances approached with sustained winds of 195 kilometres per hour and higher gusts.

It was the largest evacuation in Florida's history, surpassing the 1.3 million people urged to leave when Hurricane Floyd threatened but missed the state in 1999.

"Preparations to protect life and property should be rushed to completion," said forecaster Lixion Avila of the Miami-based National Hurricane Center. As a sign of how seriously forecasters took Frances, storm shutters were put up Thursday at the Hurricane Center.

Bush excused himself from the Republican National Convention this week in New York City, where his brother, President George W. Bush, accepted his nomination for reelection in November, to lead emergency efforts for Frances and recovery efforts in central Florida, which was devastated by Hurricane Charley, officials said.

San Salvador Island in the Bahamas reported sustained winds of 190kph when the edge of the storm's eye passed over island before pounding Cat Island, also in the Bahamas, where a resident told a Florida radio station by telephone "the wind sounds like a freight train."

But there was a little good news as Frances lost some of her steam and was downgraded one point to a level-three hurricane on the Saffir-Simpson scale, which reaches a maximum of five.

The storm was likely to hit Florida over the weekend, with tropical storm winds already expected on Friday night. "The consequences of not evacuating could be very severe," an official said. -AFP