FERNANDO DE NORONHA, Brazil — Brazilian military planes found a three-mile path of wreckage in the Atlantic Ocean today, confirming that an Air France jet carrying 228 people crashed in the sea, Defense Minister Nelson Jobim said.

Jobim said the discovery confirms that the plane went down in that area, hundreds of miles from the Brazilian archipelago of Fernando de Noronha.

He said the strip of wreckage included metallic and nonmetallic pieces, but did not describe them in detail. No bodies were spotted in the crash of the Airbus in which all aboard are believed to have died.

The discovery came just hours after authorities announced they had found an airplane an airplane seat, an orange buoy and signs of fuel in a part of the Atlantic Ocean with depths of up to three miles.

A U.S. Navy P-3 surveillance plane arrived in Brazil this morning to help if needed, U.S. Defense Department spokesman Bryan Whitman said.

The French minister overseeing transportation, Jean-Louis Borloo, has dispatched to the debris site a research ship that can deploy unmanned submarines to explore depths of up to 19,600 feet. The U.S. also was considering contributing unmanned underwater vehicles in the search, according to a defense source who spoke on condition of anonymity because he was not authorized to speak on the record.

The discovery of debris came more than 24 hours after the jet went missing, with all 228 aboard feared dead.

Rescuers were still scanning a vast sweep of ocean extending from far off northeastern Brazil to waters off West Africa. The 4-year-old plane was last heard from at 0214 GMT Monday (7:14 p.m. PDT Sunday). If no survivors are found, it would be the world’s worst aviation disaster since 2001.

Investigators on both sides of the ocean are trying to determine what brought the Airbus A330 down, with few clues to go on so far. Potential causes could include violently shifting winds and hail from towering thunderheads, lightning or some combination of other factors.

The crew gave no verbal messages of distress before the crash, but the plane’s system sent an automatic message just before it disappeared, reporting lost pressure and electrical failure. The plane’s cockpit and “black box” recorders could be thousands of feet below the surface.

The chance of finding survivors now “is very very small, even nonexistent,” said the French minister overseeing transportation, Jean-Louis Borloo. “The race against the clock has begun” to find the plane’s two black boxes, which emit signals up to 30 days.

Borloo called the A330 “one of the most reliable planes in the world” and said lightning alone, even from a fierce tropical storm, probably couldn’t have brought down the plane.

“There really had to be a succession of extraordinary events to be able to explain this situation,” Borloo said on RTL radio today.

French police were studying passenger lists and maintenance records, and preparing to take DNA from passengers’ relatives to help identify any bodies.

France’s Defense Minister Herve Morin said “we have no signs so far” of terrorism, but all hypotheses must be studied.

On board the flight were 61 French citizens, 58 Brazilians, 26 Germans, nine Chinese and nine Italians. A lesser number of citizens from 27 other countries also were on the passenger list, including two Americans.