SAN FRANCISCO (AP) - A limousine taking nine women to a night in town to celebrate a newly-wed bride erupted in flames, killing five of the passengers who were trapped inside as the other four escaped with burn and smoke inhalation injuries, authorities said.

Relatives said the bride was among the dead.

The driver, who was not hurt, told investigators that he was driving the women on the San Mateo-Hayward Bridge on Saturday night when one of them complained of smoke inside the passenger compartment, San Mateo County Coroner Robert Foucrault said.

He said he pulled over, got out, and saw the back of the 1999 Lincoln Town Car fully engulfed in flames, Mr Foucrault said.

By the time firefighters rushed to the scene and put out the fire, authorities found five badly burned bodies huddled near the partition that separates the driver from the passengers.

"My guess would be they were trying to get away from the fire and use that window opening as an escape route," Mr Foucrault said.

He said other motorists helped three women get out of the rear right door, and a fourth woman managed to squeeze through the partition.

The San Mateo Fire Department was investigating the cause of the fire, while the coroner's office was working with the California Highway Patrol to determine whether a crime occurred.

"We don't believe there is," Mr Foucrault said.

The company that operated the limo was identified as Limo Stop, which offers service through limousines, vans and SUVS.

Relatives told the San Francisco Chronicle and the San Jose Mercury News that one of the dead was Ms Neriza Fojas, 31, a registered nurse from Fresno who recently wed and was planning to repeat her marriage vows in the Philippines next month.

A photo taken by a witness and broadcast on KTVU-TV showed flames shooting from the back of the limo.

Aerial video shot after the incident showed about one-third of the back half of the limousine had been scorched by the fire. Its taillights and bumper were gone and it appeared to be resting on its rims, but the remainder of the vehicle did not appear to be damaged.

The driver - 46-year-old Orville Brown - was the only person to escape unhurt.

His brother told the Chronicle the flames spread before he could help the women escape.

"He tried to get everybody out," Mr Lewis Brown Jr. said. "He told me 'Man, it was so fast.' He said, 'I've never seen anything like it in my life."'

Autopsies of the five women were being conducted, and medical examiners will try to identify them by using dental records, Mr Foucrault said.

The four other women who escaped the fire were being treated at nearby hospitals, the highway patrol said. Two of them were in critical condition.