By Rafael A. Olmeda and Mike Clary
Sun-Sentinel

MIAMI — At least three people died early Friday when a rusty, steel-hulled boat ran aground off Virginia Key and many of the 42 people thought to be onboard jumped into the sea in an attempt to reach shore.

Elee Erice, a spokeswoman for U.S. Customs and Border Protection, said that of the 13 survivors being held at the agency's Pembroke Pines lockup, four were Brazilian and nine were from the Dominican Republic.

Fourteen survivors were being held aboard the Coast Guard cutter Dolphin, Erice said. Their nationalities, and those of the dead, all men, were unknown, she added.

The search for others on the vessel continued.

The 40-foot boat, flying a Dominican flag, was spotted about 8 a.m., according to Miami-Dade Fire Rescue spokesman Lt. Arnold Piedrahita.

"When they saw the Coast Guard approaching, they started jumping off and trying to swim to shore," Piedrahita said.

Once on scene, Fire Rescue divers threw life vests to migrants in the water and at times jumped from hovering helicopters to help struggling survivors swim to safety.

During the day, Coast Guard and Miami police used boats and helicopters to search the sea and the Virginia Key area for others who may have been onboard.

In all, 26 Miami-Dade Fire Rescue units were employed in the search, Piedrahita said.

Late Friday, federal officials said they did not know if the captain of the vessel was in custody, and, pending further investigation, they declined to characterize the incident as a smuggling operation.