The search for the missing Malaysian passenger jet proved futile again Sunday, despite a new French report of possible debris from the plane's wreckage floating in the Indian Ocean.
Planes and ships from several countries flew and sailed over the remote waters 2,500 km southwest of Australia for a fourth day, but found nothing of significance. The search will continue Monday.
France reported picking up satellite-generated radar echoes of possible debris in the southern Indian Ocean, similar to earlier satellite photo images collected by Australia and China. That led Australian Prime Minister Tony Abbott to voice the hope that a breakthrough is possible to find the Boeing 777 with 239 people aboard.
"We have now had a number of very credible leads and there is increasing hope, no more than hope, no more than hope, that we might be on the road to discovering what did happen to this ill-fated aircraft."
Saturday, a search plane spotted debris, including a wooden shipping pallet, although it was not clear whether the pallet came from a passing ship. But a New Zealand military plane that diverted to the location found only seaweed.
The Malaysia Airlines jet disappeared while on a planned flight from Kuala Lumpur to Beijing. There has been no firm evidence so far of what happened to the jet.
Investigators are not ruling out anything, including catastrophic mechanical failure, pilot sabotage and terrorism. They say it is possible someone with knowledge of planes diverted it far off course.
Twenty-six nations have been hunting for the plane across an area covering more than seven million square km, from Kazakhstan to the southern Indian Ocean.