Previous Coverage: Flight MH370: Air force boss backtracks on aircraft U-turn (March 12)

See the latest developments here

5PM UPDATE: Malaysia's air force chief has denied remarks attributed to him that Malaysia Airlines' missing Boeing 777-200 was tracked by military radar to the Strait of Malacca, far from its planned route.

General Rodzali Daud says such reports in local media are untrue but it is possible the plane had turned back. He was reported as saying the flight was last detected by military radar at the Strait of Malacca, off Malaysia's west coast.

Now he's saying he "did not make any such statements" but the air force had "not ruled out the possibility of an air turn-back."

Meanwhile, Vietnam says it's scaling back some of its search activities until the situation is clarified.

"We've decided to temporarily suspend some search and rescue activities, pending information from Malaysia," Vietnam's deputy minister of transport Pham Quy Tieu says.

2PM UPDATE: Air patrols and sea searches have resumed for a fifth day on both sides of the Malay peninsular for any sign of Malaysia Airlines' missing Boeing 777-200.

Search authorities widened their scrutiny to include the Malacca Strait between the western Malaysian coast and Indonesia after reports military had radar data showing the plane had flown into the area.

This is well away from the initial search area in the Gulf of Thailand where the plane was last reported before all signals ceased.

The lack of any wreckage has kept alive all the theories to the plane’s disappearance, from an accident to the possibilities of a hijacking or sabotage.

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In earlier developments:

• Military radar shows Flight MH370 changed course
• Still no signs of missing aircraft or reasons for its disappearance
• Search in confusion and disarray as authorities contradict each other
• Iranians identified as stolen passport users
• Co-pilot previously invited passengers into cockpit

In a sensational development in the disappearance of Malaysia Airlines Flight 370, military sources say the missing aircraft changed course and flew for an hour after contact was lost.

Local media reports quoting air force chief General Rodzali Daud say after the aircraft stopped communicating with ground controllers, it changed course sharply, from heading northeast to heading west, and flew hundreds of kilometres across Peninsular Malaysia and out over the Strait of Malacca, before the tracking went blank.

While this report has been carried by the New York Times and other western media agencies, it has not been confirmed by other Malaysian authorities running the now four-day-old search, which appears to be in a state of confusion and disarray.

The government and the airline have released imprecise, incomplete and sometimes inaccurate information, with civilian officials contradicting military leaders.

A spokesman for the prime minister’s office, quoted by the Times, said other senior military officials confirmed there was no evidence the plane had recrossed the Malaysian peninsula but may have attempted to turn back.

Malaysia Airlines, meanwhile, said authorities were “looking at a possibility” that the plane was headed to Subang, an airport outside Kuala Lumpur that handles mainly domestic flights.

According to the General Daud’s account, the last sign of the plane was recorded at 2:40am and the aircraft was then near Pulau Perak, an island more than 100 miles (160km) off the western shore of the Malaysian peninsula.

Authorities had earlier said the plane, which took off at 12.20am, may have attempted to turn back to Kuala Lumpur, though contact was lost at 1.30am.

On Monday, authorities in a previously unexplained move, expanded the search area to include waters west of the Malaysian peninsula. as well as the last known position of the plane in the Gulf of Thailand and South China Sea between Malaysia and Vietnam.

No debris found
No floating wreckage or debris has been found of Flight MH370, which was carrying 227 passengers and 12 crew members on a flight from Kuala Lumpur to Beijing. No distress signals were recorded.

The failure of one sighting after another has forced investigators to widen their search to a radius of 100 nautical miles, up from 50 nautical miles.

The waters of the Gulf of Thailand and South China Sea have a mean depth of 45m, which is nearly 19m less than the length of the Boeing 777-200 aircraft.

Stolen passport holders identified
One of the two Iranians using stolen passports was an Iranian travelling to Germany to reunite with his mother in Germany.

Malaysia's national police chief, Inspector-General Khalid Abu Bakar, named him as 19-year-old Pouria Nourmohammadi Mehrdad, whose mother contacted Malaysian authorities when he failed to arrive on a connecting flight to Frankfurt.

Mehrdad was using a passport reported stolen in Thailand last year from 30-year-old Austrian Christian Kozel.

The second man has been identified as Delavar Seyed Mohammedreza, 29, who was also trying to get to Europe by using a stolen Italian passport. Neither is suspected of having terrorist connections.

Co-pilot entertained passengers
The co-pilot of Flight MH370 is said to have invited two passengers into the cockpit on a previous flight, in an alleged breach of security.

The claim, from a woman who released photos of herself and a friend with the pilots taken during the December 2011 flight, comes as officials say they are probing whether crew actions – among other possibilities such as hijacking or sabotage – could have caused the disappearance.

Jonti Roos, a South African traveling in Australia, told The Wall Street Journal they were invited by the pilots to travel in the cockpit while lining up to board the plane.

Thereafter, she sat with the co-pilot, Fariq Abdul Hamid, and the flight's captain from takeoff in Phuket, Thailand, to landing at Kuala Lumpur, and took photos with them while the plane was in the air.

Malaysia Airlines says it’s "shocked" by the allegations against Fariq and takes the claims "very seriously." However, company executives weren't immediately able to confirm the veracity of Ms Roos' account.