More satellite images have given searchers the latest clues in the hunt for the downed Malaysian jetliner, as planes flew out of Australia on Thursday trying to spot 122 objects seen floating in the turbulent Indian Ocean where officials believe the missing passenger jet may have crashed.

Almost two-thirds of the 239 people who died on the flight were from China, and the first search plane in the air was a Chinese Ilyushin IL-76 aircraft.

In total, 11 planes and five ships are set to scour a search area 2,500 kilometers (1,550 miles) southwest of Perth on Australia’s western coast, but the Australian Maritime Safety Authority cautioned that weather was expected to deteriorate later Thursday.

Nineteen days into the mystery of Flight 370 that vanished early March 8 en route from Kuala Lumpur to Beijing, the discovery of the objects that ranged in size from 1 meter (3 feet) to 23 meters (75 feet) offered “the most credible lead that we have,” a top Malaysian official said Wednesday.

A search Wednesday for the objects — seen by a French satellite — was unsuccessful, echoing the frustration of earlier sweeps that failed to zero in on three objects seen by satellites in recent days.

With the search in motion, Malaysian officials again sought to assuage the angry relatives of the flight’s 153 Chinese passengers. But Defense Minister Hishammuddin Hussein also expressed exasperation, pointedly saying Chinese families “must also understand that we in Malaysia also lost our loved ones,” as did “so many other nations.”

The latest satellite images, captured Sunday and relayed by French-based Airbus Defense and Space, are the first to suggest a debris field from the plane, rather than just isolated objects. The items were spotted in roughly the same area as other objects previously seen by Australian and Chinese satellites.

At a news conference in Kuala Lumpur, Hishammuddin said some of them “appeared to be bright, possibly indicating solid materials.”

But experts cautioned that the area’s frequent high seas and bad weather and its distance from land complicated an already-trying search.

“This is a really rough piece of ocean, which is going to be a terrific issue,” said Kerry Sieh, director of the Earth Observatory of Singapore. “I worry that people carrying out the rescue mission are going to get into trouble.”

Officials from the Australian Maritime Safety Authority said Thursday’s search was split into two areas totaling 78,000 square kilometers (30,000 square miles).

Planes and ships from the U.S., China, Japan, South Korea, Australia and New Zealand are involved in the hunt, hoping to find even a single piece of the jet that could offer tangible evidence of a crash and provide clues to the location of the wreckage.

Malaysia said Monday that an analysis of the final known satellite signals from the plane showed that it had gone down in the sea, with no survivors.

That data greatly reduced the search zone to an area estimated at 1.6 million square kilometers (622,000 square miles), about the size of Alaska.

“We’re throwing everything we have at this search,” Australian Prime Minister Tony Abbott told Nine Network television.

“This is about the most inaccessible spot imaginable. It’s thousands of kilometers from anywhere,” he later told Seven Network television.

Malaysia has been criticized over its handling of one of the most perplexing mysteries in aviation history. Much of the most strident criticism has come from relatives of the Chinese passengers, some of whom expressed outrage that Malaysia essentially declared their loved ones dead without recovering a single piece of wreckage.

At a hotel banquet room in Beijing on Wednesday, a delegation of Malaysian government and airline officials explained what they knew to the relatives. They were met with skepticism and even ridicule by some of the 100 people in the audience, who questioned how investigators could have concluded the direction and speed of the plane. One man later said he wanted to pummel everyone in the Malaysian delegation.

“We still have hope, but it is tiny, tiny,” said Ma Xuemei, whose niece was on the flight. “All the information has been confusing and unreliable.”

China dispatched a special envoy to Kuala Lumpur, Vice Foreign Minister Zhang Yesui, who met Prime Minister Najib Razak.

China’s support for families is likely why authorities — normally wary of any spontaneous demonstrations that could undermine social stability — permitted a rare protest Tuesday outside the Malaysian Embassy in Beijing. Relatives chanted slogans, threw water bottles and briefly tussled with police who kept them from a swarm of journalists.

Meanwhile, a U.S.-based law firm filed court documents that often precede a lawsuit on behalf of a relative of an Indonesian-born passenger. The filing in Chicago asked a judge to order Malaysia Airlines and Chicago-based Boeing Co. to turn over documents related to the possibility that “negligence” caused the Boeing 777 to crash, including any documentation about the chances of “fatal depressurization” in the cockpit.

Though officials believe they know roughly where the plane is, they don’t know why it disappeared shortly after takeoff. Investigators have ruled out nothing — including mechanical or electrical failure, hijacking, sabotage, terrorism or issues related to the mental health of the pilots or someone else on board.

And finding the wreckage and the plane’s flight data and cockpit voice recorders is a major challenge. It took two years to find the black box from Air France Flight 447, which went down in the Atlantic Ocean on a flight from Rio de Janeiro to Paris in 2009, and searchers knew within days where that crash site was.

The batteries on the recorders’ “pingers” are designed to last 30 days. After that, the pings begin to fade in the same way that a flashlight with failing batteries begins to dim, said Chuck Schofield of Dukane Seacom Inc., a company that has provided Malaysia Airlines with pingers in the past. Schofield said the fading pings might last five days before the battery dies.

If a general area is pinpointed for the wreckage, experts says depths will area range from 3,000 to 4,500 meters (10,000 to 15,000 feet).

(AP)