UPDATE: Norwegian ship the St Petersburg has reached the area of the Indian Ocean where possible debris of missing Malaysia Airlines flight MH370 has been spotted.
"The ship has arrived at the site to take part in the search," said Cecilie Moe, spokeswoman for Norwegian shipping company Hoeeg Autoliners, tonight.
Planes and ships today converged on a remote section of the Indian Ocean 2500km from Perth, searching for debris that may be parts of the missing plane.
The search area, which had been refined again, emerged today after satellite imagery indicated the debris, with one piece about 24m long.
A search for the missing plane will resume in the Indian Ocean tomorrow.
The Australian Maritime Safety Authority tweeted tonight that an Australian RAAF P3 crew were unable to locate debris.
Cloud and rain had limited visibility, it said.
In an earlier briefing, AMSA said an RAAF aircraft arrived at the area just before 11am Perth time.
John Young, emergency response division general manager at AMSA, said the focus was to continue the search with all available ships and aircraft.
"It's probably the best lead we have right now but we have to get there, find them, see them, assess them, to know whether it's really meaningful or not,” he said.
Malaysia says the two objects gave reason for hope.
“Every lead is a hope,” Transport Minister Hishammuddin Hussein said.
Prime Minister Tony Abbott told Parliament today that Australia may have found pieces of MH370.
In a shock development earlier today, Mr Abbott said AMSA had received satellite images of "objects possibly related to the search".
"Following specialist analysis of this satellite imagery two possible objects related to the search have been identified," The Prime Minister said.
Mr Abbott said a RAAF Orion had been sent to the area to attempt to locate the objects and determine if they were from the Malaysia Airlines 777.
He said he had spoken to Malaysian Prime Minister Najib Razak to inform him of the development.
Mr Abbott said there was no guarantee the objects sighted were parts of the missing jet.
A reporter from The West Australian on board a US P8A Poseidon plan said the aircraft is searching an area about 1500 miles [2414km] south-west of Perth.
Items may be floating on the surface.
AMSA released satellite images of two separate areas of debris, one with objects about 24m long and the second with objects about 5m long.
"Satellite imagery provided to AMSA of objects that may be possible debris of the missing Malaysia Airlines Flight MH370 in a revised area 185km to the south east of the original search area," AMSA said.
"The imagery has been analysed by specialists in Australian GeoSpacial-Intelligence Organisation and is considered to provide a possible sighting of objects that has resulted in a refinement of the search area."
The aircraft is flying at about 500 feet above sea level in an area which is about 200 miles south of the original search area.
The new search area is based on information received by the US crew just before it left Perth at 8.45am.
A US spokesman said they were investigating a report of what could be small to medium sized objects seen on the surface.
The US plane will run a grid search over the area and drop sono buoys that will transmit information to mark the area and measure ocean drift.
They will employ radar, cameras and visual observation.
It is believed that two RAAF aircraft will follow up when the US aircraft confirms something is in the water.
The plane could go as low as 300 feet.
"From where it is now, visibility is very good – we can see the white-capped wave and a cargo vessel,” reporter Malcom Quekett said.
"The task of locating these objects will be extremely difficult and it may turn out that they are not related to the search for flight MH370," Mr Abbott said.
In a briefing, AMSA said a RAAF aircraft arrived at the area just before 11pm Perth time.
Three more military aircraft, including two from the United States and New Zealand, will arrive soon.
An Australian Hercules will drop marker buoys in the area highlighted by the satellite imagery.
The marker buoys provided information about water movement to assist drift modelling.
“They will provide an ongoing reference point if the task of relocating the objects becomes protracted,” AMSA said.
Weather conditions in the area are moderate but visibility is poor.
Mr Young said: “The objects are relatively indistinct on the imagery,” he said. “The are objects of a reasonable size and probably awash with water.”
The largest was assessed as being about 24 metres.
Mr Young said the ocean in the area was thousands of metres deep.
“AMSA is doing its level best to find anyone that might have survived,” he said when asked what advice he had for families of the 239 people who were on the missing flight.
Mr Young cautioned the objects would be difficult to locate.
“It's probably the best lead we have right now but we have to get there, find them, see them, assess them, to know whether it's really meaningful or not,” he said.
Mr Young said in AMSA'S experience there was usually debris floating out in that area, but on this occasion the size, and the fact that there were a number, made it worth looking at.
He cautioned against any hasty expectations of an outcome of the search because of unfavourable weather conditions.
“We may get a sighting, we may not. We may get it tomorrow, we may not,” he said.
“But we will continue to do this until we locate those objects or we are convinced that we cannot find them.”
MH370 disappeared just hours after leaving Kuala Lumpur for Beijing early on Saturday March 8.
News emerged overnight that a simple and cheap app that helped find an Air France jetliner that went missing in 2009 was not bought by Malaysia Airlines.
The application, sold at $10 per flight wholesale, could have helped investigators triangulate the plane's position even after the transponder and ACARS communications services turned off, the Washington Post reported.
According to reports, the app wasn't in operation on missing Malaysia Airlines flight MH370.
The app, called Swift, uses satellites to transfer data such as direction, speed and altitude in a constant live stream that continues to run as long as the plane is running.
Swift data was used to find the Air France plane that crashed in 2009 by helping rescue teams to narrow the search area to about 64 kilometres in the Atlantic Ocean.
It took them just five days to find the missing craft. The Malaysia Airlines plane has now been missing for 13 days and has a search zone of 2.24 million square nautical miles.
An industry expert, speaking to the Washington Post on condition of anonymity, said that Swift acted in a similar way to a mobile phone that sends data to a satellite.
He said that if the full application is bought and in operation, data such as engine performance, fuel consumption, speed, altitude and direction is sent in real time to the airline company and the plane's manufacturers.
The official, who spoke to AFP on condition of anonymity, confirmed the request related to the Malaysia Airlines Flight 370 probe -- first reported by the New York Times -- without offering further comment.
Malaysian police removed the flight simulator from Captain Zaharie Ahmad Shah's home on Saturday.