SANTO DOMINGO, Dominican Republic (AP) -- A Frenchwoman attempting to break the world free diving record drowned, initial autopsy reports suggested Sunday.

On Saturday, Audrey Mestre was pulled up by scuba divers 9 minutes, 44 seconds after she sunk below the surface without oxygen. Attached to a 200-pound weighted sled, Mestre plunged more than 500 feet below the surface.

"We don't know exactly what happened,'' said Carlos Serra, president of the Miami-based International Association of Free Divers.

An initial autopsy conducted in Santo Domingo found drowning to be the cause of death, but a final report could take weeks to be released, he said.

"We believe something hit the sled,'' Serra said earlier. "When she came out of the water she was foaming from the mouth and bleeding.''

The 28-year-old Mestre reached her target depth of 561 feet near La Romana, Serra said. But in order for it to be considered a record, she needed to return to the surface safely, he said.

Jeff Blumenfeld, a spokesman for Mares, an Italian diving equipment manufacturer that sponsored Mestre, said 13 scuba divers monitored the dive for safety. Usually the diver descends and ascends on a single breath. But when something appeared to go wrong, Mestre was given oxygen on the ascent by one of the divers.

After the autopsy, her body was taken to a mortuary in Santo Domingo, the capital. Serra said Mestre's parents were on their way from Mexico, where they live, and would decide where she would be buried.

On a free dive, the diver plunges to a great depth and comes straight back to the surface. Decompression is not needed because the diver has not breathed in any air during the dive.

Mestre was born in St. Denis, France, six miles north of Paris, and lived in Miami with her Cuban husband, Francisco "Pipin'' Ferreras, also a free diver.

Serra said she was trying to break the "no limits'' dive world record recognized by his association: 531½ feet achieved by Ferreras, off Cozumel, Mexico in January 2000.

In another deep dive, Tanya Streeter reached a depth of 525 feet in Turks and Caicos in August. Officials with the International Association for the Development of Apnea, based in Switzerland, said Streeter's dive broke men's and women's records for dives it had administered.

But Serra said his association recognizes Ferreras' dive as the men's world record.

He said Mestre had trained hard for Saturday's dive, in which she was only supposed to be down for about three minutes.

On Oct. 4, Mestre plunged to 544.52 feet at the same spot. On Wednesday, she also went to 561 feet in a practice dive off La Romana, Blumenfeld said.