Missing MH370: Friday's search ends "without any sightings"

PERTH: Spotter planes spent a second fruitless day scouring a remote stretch of the Indian Ocean for wreckage of Flight MH370.

Australian and US military aircraft usually used for anti-submarine operations criss-crossed the isolated search area 2,500km southwest of Perth, looking for two floating objects that had shown up on grainy satellite photos taken several days before.

Although the images were too indistinct to confirm as debris from Flight MH370, Australian and Malaysian officials said they represented the most "credible" leads to date in the hunt for the plane and its 239 passengers and crew.

Friday's search concluded "without any sightings", the Australian Maritime Safety Authority (AMSA) said in a statement.

The planes flew low under the cloud cover rather than rely on radar, after poor weather the day before hampered the search.

"We replanned the search to be visual, so aircraft flying relatively low, with very highly skilled observers looking out of the windows," said AMSA official John Young.

"This means aircraft operating more closely together and we will need more aircraft for this task."

Friday's aerial contingent comprised three Australian air force P-3 Orions, a US Navy P-8 Poseidon and a civil Bombardier Global Express jet.

The distance from the west coast of Australia allows the planes only about two hours of actual search time before they must turn around with enough fuel to get back to Perth.

Two merchant ships were helping with the search, but Australia's HMAS Success, which is capable of retrieving any wreckage, was still days away.

"This is going to be a long haul," acting Transport Minister Datuk Seri Hishammuddin Hussein told a daily press briefing in Kuala Lumpur.