Two objects in the southern Indian Ocean remain the target for Australian authorities as the search for missing Malaysia Airlines flight MH370 continues on Friday.
Military aircraft and merchant ships are racing to a position in the southern Indian Ocean about 2500 kilometres southwest of Perth, where a satellite identified two floating objects.
One measured about 24 metres, while the other one was smaller.
Australian authorities say they are possible remnants of the Boeing 777 that went missing on a March 8 flight from Kuala Lumpur to Beijing, carrying 239 people.
10:40PM: As darkness closes in on the search area over the Indian Ocean, the operation to find a link to satellite images showing potential debris from the missing Malaysia Airlines flight MH370 is started to come to a halt.
Australia's AP-3C Orion aircraft has landed in Perth after it was unable to find any sight of the debris.
10:10PM: Hishammuddin Hussien, Malaysia's Acting Transport Minister, says that if the objects in the South Indian Ocean are confirmed to be from the missing Boeing 777-200, a new phase of the search will focus on an international operation to find the black box recorder.
He said that the black box is the vital clue in establishing exactly what happened to the MH370.
The black box of an aircraft records extensive data from the flight, including engine information, and changes to a plane's controls, altitude and oxygen levels. More importantly, it records conversations from within the cockpit, which will prove crucial to unlocking the mystery of the missing MH370.
While the black box would have been unaffected by the shutdown of MH370's transponders, the depth of the Indian Ocean - which reaches as deep as 4000 metres - could prove a major obstacle.
Professor Chari Pattiaratchi, from the University of Western Australia, told Fairfax that the search for the black box could take years.
"You can't go in an aircraft and have a look; you have to send ships and underwater vehicles to recover [the wreckage]," he said.
10:10PM: A Norwegian ship on Thursday reached the Indian Ocean area where possible debris of the missing Malaysia Airlines MH370 plane was spotted, shipping company Hoeeg Autoliners said.
"The ship has arrived at the site to take part in the search," said Cecilie Moe, spokeswoman for the Norwegian company.
The car carrier was on its way from Madagascar to Melbourne when it got a request from Australian authorities to assist in investigating the objects spotted by satellite four days ago in one of the remotest parts of the globe, around 2,500 km (1,500 miles) southwest of Perth.
According to another Hooeg Autoliners spokesperson, Christian Dahll, the search window for Thursday was limited since sunset was at 1300 GMT.
The "St. Petersburg" vessel, a vehicles carrier, was on its way from Port Louis in Mauritius to the Australian city of Melbourne, when it was requested by the Australian authorities to reroute in order to identify the debris spotted by satellite in the southern Indian Ocean.
9:48PM: Defence Minister David Johnston says that authorities will have to wait "two or three days" to find out definite and confirmed information on the possible discovery of debris from the missing Malaysia Airlines flight MH370.
Johnston said that the operation to find debris is a “logistical nightmare”.
“This is a terribly complex logistical operation to identify what we have found via the satellite,” he said.
“We are in a most isolated part of the world, in fact it probably doesn’t get, if I can be so bold, more isolated."
“We are doing everything we can to try to solve this potentially tragic mystery.”
John Young of the Australian Maritime Safety Authority (AMSA) was cautious not to raise hopes, saying the satellite imagery shows "a sort of blob" with no features to distinguish it as aircraft fragments.
"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," the emergency response division manager said.
Water in the area is thousands of metres deep and searchers are battling poor visibility, with last light due about midnight (AEDT) on Thursday.
"Every lead is a hope," Malaysian Transport Minister Hishammuddin Hussein told reporters in Kuala Lumpur.
"This time I just hope that it is a positive development."
9:30PM: Malaysia Airlines chief executive Ahmad Jauhar Yahya has announced that the company will fly relatives of passengers and crew on board the missing flight MH370 to Perth if the objects spotted on Australia satellites are confirmed to be of the plane.
He said that the company wants to help families be as close to the plane as possible when it is found.
8:12PM: Australia has been co-ordinating the search operation in the southern Indian Ocean, which is based on calculations by United States experts who have analysed MH370's fuel range.
If the debris belongs to the aircraft, it indicates MH370 ended up thousands of kilometres from its planned destination, raising further questions about why it changed course.
But the priority for AMSA remains identifying the bobbing objects.
It is not uncommon to find floating debris, including shipping containers that have been washed overboard, Mr Young said.
"On this particular occasion, the size and the fact that there are a number located in the sea at the same area really makes it worth looking at."
An RAAF C-130 Hercules has dropped marker buoys at the location, and military aircraft from Australia, New Zealand and the US are combing the area.
A merchant ship was due to reach the area by 6pm (AEDT).
"They will be difficult to find. They might not be associated with the aircraft and we have plenty of experience of that in other searches," Mr Young said.
The search area is a long way from the Australian mainland and once aircraft reach the location, they have about only two hours of fuel before having to return to base.
Asked about his message to the family and friends of people on board flight MH370, Mr Young said Australia would continue to search until it found something.
"AMSA is doing its level best to find anyone who may have survived," he said.
Australia is sharing its information with 25 other countries involved in the search operation, and Prime Minister Tony Abbott confirmed on Thursday he had spoken to his Malaysian counterpart about the latest update.
Unfavourable weather may hinder the search.
"Weather conditions are moderate ... and poor visibility has been reported," an AMSA spokesman said.
"This will hamper both air and satellite efforts."
Here's how the news unfolded earlier today:
Australian authorities have found objects that could be related to missing Malaysia Airlines flight MH370 and have sent planes to search the area.
7:16PM All the major points of the mystery behind missing Malaysian Airlines flight MH370 all put together in this one handy infographic by AFP.
7:02PM This is a graphic of the search zone put together by the Wall Street Journal.
6:16PM Malaysia's prime minister Moh Najib Tun Razak has tweeted, saying he received a call from Tony Abbott and he was now discussing matters with his chief of defence force.
6:01PM The Australian Maritime Safety Authority has provided the satellite imagery they referred to in today's earlier press conference.
"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."
"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."
5:32PM: In case you missed it, this is the press conference given by John Young of the Australian Maritime Safety Authority updating what had been detected by satellites and the mission to discover what those objects are.
5:15PM Pictures from the Facebook page of HMAS Success departing Fremantle were posted 15 hours ago. The ship has been sent to where the objects were spotted but it's not expected to reach the area for days.
5:04PM Watch our latest bulletin on this developing story:
4:58PM: Malaysia’s defence minister Hishammuddin Hussein released a brief statement on the new findings.
"At 10:00 this morning, Prime Minister Dato’ Seri Najib Razak received a call from Prime Minister Tony Abbott of Australia, informing him that ‘two possible objects related to the search’ for MH370 had been identified in the Southern Indian Ocean. The Australian High Commissioner has also briefed me on the situation," the statement said.
"At this stage, Australian officials have yet to establish whether these objects are indeed related to the search for MH370."
4:32PM: A RAAF aircraft arrived at the area just before 2pm (AEDT) and three more military aircraft, including two from the United States and New Zealand, are expected to reach the area later this evening.
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.
A merchant ship that responded to a shipping broadcast issued by Rescue Coordination Australia on Monday is expected to arrive in the area about 6pm (AEDT)
4:15PM: The AMSA says it continues to hold grave concerns for the passengers and crew on board the missing Boeing 777-200.
A statement released by the safety authority says that poor visibility is hindering the search operation in the Southern Indian Ocean after AMSA’s Rescue Coordination Centre Australia received satellite imagery of objects possibly related to flight MH370.
3:57PM: ABC US foreign editor Jon Williams has said the US naval vessel heading to the possible debris site had picked up information about the area using radar searches.
"Crew on @USNavy P-8 spotter tell @WrightUps "significant radar returns" coming from site where possible #MH370 objects spotted," he said on his Twitter account.
3:31PM: John Young of the Australian Maritime Safety Authority said that an image provided by a satellite showed two objects, one that was at least 24 metres in size.
He said that there was possible debris south of the area that had been searched in the past two days.
“Those who are experts indicate they are credible sightings,” Young said.
“The indication to me is of objects that are of reasonable size and awash with water, bobbing up and down on the surface.”
Young stressed that there was no confirmation the two objects were related to missing flight MH370. He also said that the objects may be difficult to locate.
"Our experience is that there is debris out there," Young said.
"It can be containers from ships for example, falling overboard. On this particular occasion, the size and that there are a number in the same area really makes it worth looking at.
"But I don't want to speculate until we get there and we see them."
However, he said that it was a promising enough lead to be worth sending planes to take a closer look.
Four aircraft had been diverted to the area to investigate the objects: A RAAF Orion and three RNZ Orion aircraft.
A RAAF C130 Hercules aircraft has been tasked to drop marker buoys to provide information about water movement and assist in drift modeling.
A ship from Malaysia was expected to reach the area by around 6pm (AEST).
Young said that while the weather conditions in the area were moderate, there was very poor visibility and that this would hamper any search efforts.
HMAS Success is some days away from the area, and is equipped to recover any items from the area.
"There are many steps before we could [retrieve] it," Young said.
"What we're looking for is a confirmation that it does belong to the aircraft or does not."
- FBI 'probing deleted data'
- Was missing flight 'swapped' mid-air?
- MH370: The simplest explanation yet
- Pilots 'unconscious after take-off'
2:56PM: ABC News (US) quotes US Navy sources saying a US P-8 is nearing the search area where the satellite images show two items.
2:01PM: Prime Minister Tony Abbott has said Australian Maritime Safety Authority has received credible information that two objects located in their search have been linked to missing Malaysian Airlines flight MH37.
Satellite imagery had spotted the two objects in the Southern Indian Ocean.
Australia was leading the search in what authorities in the "south corridor" as part of the international search for the missing flight.
The prime minister said “two possible objects related to the search have been identified” to parliament.
A RAAF Orion has been sent to the location and was due to arrive around now. Three more aircraft are due to fly to the location.
"The Australian Maritime Safety Authority has received information, based on satellite imagery, of objects possibly related to the search," the prime minister said.
"Following specialist analysis of the this satellite imagery two possible objects related to the search have been identified.
"I can inform the House that a RAAF Orion has been diverted to attempt to locate the objects. This Orion is expected to arrive in the area at about this time.
"Three more aircraft will follow this Orion. They are tasked for a more intensive follow-up search.
"I have spoken to my Malaysian counterpart Prime Minister Najib Razik, and informed him of these developments.
"I must inform the house 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 MH 370."