The search for missing Malaysia Airlines flight MH370 has resumed thousands of kilometres off the west coast of Australia.
The first of five search planes flew out of the country on Friday to search one of the most remote places on Earth for objects that might be from the the missing aircraft.
This is a lead, it's probably the best lead we have right now.
Australian authorities said early Friday that efforts were resuming, with a Royal Australian Air Force Orion leaving at dawn for the area about 2,300 kilometres from western Australia.
China's government also said it was sending three warships to join the search.
The planes and ships are checking to see if two large objects spotted on satellite imagery are debris from the jet that disappeared on March 8 with 239 people on board.
One of the objects was 24 metres long and the other was five metres. There could be other objects in the area, a four-hour flight from Australia's southwestern coast, said John Young, the manager of the Australian Maritime Safety Authority's emergency response division.
"This is a lead, it's probably the best lead we have right now," Young said.
He cautioned that the objects could be seaborne debris along a shipping route where containers can fall off cargo vessels, although the larger object is longer than a container, the AP news agency reported.
Young said the depth of the ocean in the latest area, which is south from where the search had been focused since Monday, is several thousand metres.
Geoffrey Thomas, the editor of airlinratings.com, also told Al Jazeera that if debris from the missing plane was found in the area, "it would present collosal challenges of actually finding the main body of wreckage".
"We're down in what's called the roaring forties, latitude 40 degrees, very strong winds, very high swells - at the moment 20 feet, they get up to 40 to50 feet," Thomas said.
Malaysian authorities have not ruled out any possible explanation, but have said the evidence so far suggests the plane was deliberately turned back across Malaysia to the Strait of Malacca, with its communications systems disabled.
They are unsure what happened next.