Hours after the deadly storm slammed ashore in densely populated southeastern Florida, its eye headed out over the Gulf of Mexico early Friday, but howling winds and pounding rain still battered Miami and surrounding areas.

Weakened to a tropical storm as it moved inland, Katrina regained hurricane strength soon after reaching the warm gulf waters where it was expected to strengthen further, causing concerns in oil markets where crude prices reached record highs on Thursday.

As the hurricane crashed ashore, a 25-year-old man was killed when a tree fell on his car, and a pedestrian was also crushed to death by a falling tree, local media reported.

Both fatalities occurred in Fort Lauderdale, just north of the area where Katrina made landfall late Thursday, becoming the sixth deadly hurricane to pummel Florida in just over one year.

Authorities also reported the death of a 79-year-old man in a car crash near Fort Lauderdale.

Katrina packed maximum sustained winds of 128 kilometers (80 miles) per hour as it landed 22 kilometers (14 miles) north of Miami, with gusts reaching 140 kilometers (92 miles) per hour.

Authorities in Miami said they were investigating reports that a vehicle was trapped under a highway overpass that partly collapsed. Emergency services also reported that a truck was dangling from an overpass near Fort Lauderdale.

A US Coast Guard crew aboard a C-130 rescue plane braved the storm during the night to search for a couple and their three children whose pleasure craft was reported missing off the Florida Keys, south of Miami.

The storm sent roof shingles, signs, tree limbs flying, and downed power lines, leaving about 1.5 million homes without electricity.

Numerous streets in Miami were flooded, stranding motorists who braved driving rain and debris despite official warnings to stay off the roads.

Greenish flares lit up the night skies as power lines short-circuited, sending entire neighborhoods into darkness.

Three people in the Miami area were hospitalized for carbon-monoxide poisoning, apparently after inhaling exhaust fumes in their garage as they sat in a car with the engine and the air conditioning running after losing power in their home, local radio reported.

Initial concerns that Katrina could swirl over offshore oil rigs in the Gulf of Mexico helped push crude prices to new highs and caused the evacuation of non-essential workers from some platforms off the southern United States.

Crude oil futures jumped to a record New York closing price of 67.49 dollars a barrel, up 17 cents from Wednesday.

But forecasts on Friday showed the storm should remain to the east of the main offshore oil fields, and would likely make a second landfall at hurricane strength in northwestern Florida Sunday.

At 0900 GMT, the center of Katrina was some 85 kilometers (50 miles) northeast of Key West, Florida, and moving westward at seven kilomters (five miles) per hour, said the Miami-based National Hurrican Center.

With maximum sustained winds of 120 kilomters (75 miles) per hour, Katrina was a Category One hurricane in the five-level Saffir-Simpson hurricane intensity scale

Fort Lauderdale airport was closed and flights to and from Miami's international airport were canceled. Ports and cruise terminals in the affected areas also shut down, as did schools and most offices.

"It's important to take this seriously," said Florida Governor Jeb Bush, a brother of the US president.

While Katrina ranked at the bottom of the Saffir-Simpson scale when it hit Florida, many hurricane-hardened residents calling radio stations said they were stunned by the punch it packed.

Authorities also warned that most hurricane fatalities typically occur after the storm has passed, often as a result of floods or downed power lines.

"In essence, this is a very dangerous storm," Governor Bush said.

News reports from southern Florida, mentioned 7.5 centimeters (three inches) of rainfall per hour for some five hours, with total accumulations in some areas surpassing 40 centimeters (15 inches).

The storm put a damper on the MTV Video Music Awards, causing the cancellation of star-studded concerts and parties, though organizers remained confident Sunday night's award ceremony in Miami would go ahead as planned.

A few hours before Katrina made landfall, workers took down from a Miami Beach hotel roof the giant statue of an astronaut that symbolizes the "Moonman" award MTV hands out at the annual ceremony.