Despite better weather, the first of five search planes dispatched to look for floating debris that could be related to missing Malaysia Airlines Flight 370 returned to base Friday without spotting anything of note.
The surveillance planes are looking for two objects photographed by a commercial satellite on Sunday bobbing in the remote and treacherous waters of the southern Indian Ocean off the west coast of Australia.
Aircraft and a merchant ship scoured the area Thursday, but found nothing in a search hindered by poor weather.
Flight 370 vanished 14 days ago with 239 people aboard, and the announcement Thursday by Australian officials that they had spotted something raised hopes of a breakthrough in the frustrating search.
On Friday, Australian Prime Minister Tony Abbott defended the decision to announce the find, saying that Australia owes it to families f those missing "to give them information as soon as it's to hand, and I think I was doing that yesterday in the Parliament."
But he reiterated a warning that two objects spotted by satellite in a remote area of the southern Indian Ocean, which are now being sought by aircraft and ships, may not be related to the search for the plane.
"It could just be a container that has fallen off a ship," he said during a visit to Papua New Guinea. "We just don't know."
His words have focused worldwide attention on Australia's part in the massive international hunt for the jetliner, which disappeared March 8 over Southeast Asia with 239 people on board.
Almost two weeks after the Boeing 777-200 dropped off radar screens, authorities still don't know why it veered dramatically off course or where it ended up.
Because of the "anxiety and apprehension" experienced by relatives of the people aboard the plane, Abbott said
Search teams that flew over the area where the two objects are thought to be located drew a blank Thursday, with poor visibility reported. Flights to the zone by long-range reconnaissance planes resumed Friday, Australian authorities said.
The search area, thousands of kilometers southwest of Perth, the main city on Australia's west coast, is "about the most inaccessible spot you could imagine on the face of the earth," Abbott said.