Even if searchers are able to miraculously pluck Malaysia Airlines flight 370's "black box" from the depths of the vast Indian Ocean, experts say it may not solve one of aviation's greatest mysteries.

Planes, ships and state-of-the-art tracking equipment are hunting for any trace of the passenger jet, which Malaysia said crashed in the forbidding waters after veering far from its intended course.

Scores of angry relatives of the Chinese passengers aboard Flight MH370 set out on a protest march to the Malaysian embassy in Beijing Tuesday to demand more answers about the crashed plane's fate.

Around 200 family members, some in tears, linked arms and shouted slogans including "The Malaysian government are murderers" and "We want our relatives back".

Malaysia said Monday its missing airliner had crashed in the Indian Ocean, extinguishing the hopes of relatives of those on board but shedding no light on why it veered so far off course.

A somber Prime Minister Najib Razak said a new analysis of satellite data on Malaysia Airlines flight MH370's path placed its last position in remote waters off Australia's west coast, "far from any possible landing sites."

An Australian plane searching the vast Indian Ocean for signs of missing flight MH370 spotted two objects on Monday which Malaysia said could be retrieved by a ship within hours.

There was no initial confirmation that the objects were linked to the Malaysia Airlines passenger jet but their sighting added to mounting reports of debris that have energized the huge multinational search for the plane two weeks after it went missing.

The sighting of a wooden pallet and other debris that may be linked to a Malaysian passenger jet raised hopes Sunday of a breakthrough in the international search for the missing plane.

The sense that the hunt was finally on the right track after more than two weeks of false leads and dead ends was reinforced by new French satellite data indicating floating objects in the southern search area.

China released Saturday a new satellite image of a large floating object possibly linked to missing Malaysian Flight MH370, boosting search efforts as anger with the pace of the operation boiled over among Chinese relatives in Beijing.

The grainy photo taken on March 18 released by the State Administration of Science Technology and Industry showed an object measuring 22.5 meters by 13 meters (74 by 43 feet) in the southern Indian Ocean.

Malaysia on Friday asked the United States to provide undersea surveillance technology to help in the search for the wreckage of a missing airliner, Pentagon officials said.

The request came as a near two-week search failed to find any debris from the Boeing 777 that disappeared off the radar after taking off from Kuala Lumpur on March 8.

Spotter planes on Friday scoured a remote, storm-tossed stretch of the Indian Ocean for wreckage from a Malaysian jet, as Chinese relatives of the missing passengers clashed with Malaysian officials over their handling of the search operation.

The Australian and U.S. aircraft criss-crossed an isolated section of ocean 2,500 kilometers (1,500 miles) southwest of Perth, looking for two floating objects that had shown up on grainy satellite photos taken several days before.

Thai radar picked up an "unknown aircraft" minutes after flight MH370 last transmitted its location but officials failed to report the findings earlier as the plane was not considered a threat, the air force said Wednesday.

The information emerged during checks of radar logs on Monday -- nine days after the Malaysia Airlines jet carrying 239 passengers and crew disappeared -- after a request from the Malaysian government, according to Air Marshal Monthon Suchookorn.

Intelligence checks on the 153 Chinese passengers aboard a missing Malaysian airliner produced no red flags, China said Tuesday, as investigators struggled to clarify events that led to the plane's dramatic disappearance.

Eleven days after contact was lost with Flight 370 and its 239 passengers and crew, there has been minimal progress in determining what transpired when the Boeing 777 was deliberately diverted off its flight path and where it might have gone.