The search for the missing Malaysia Airlines flight was descending into confusion and acrimony on Wednesday as Vietnam called off part of its search pending further information from Malaysia.

As families spent a fifth day waiting for news of flight MH370, which vanished on Friday with 239 people on board, disagreements within the international search operation were surfacing and Malaysian officials failed to clarify the aircraft's last known movements.

India announced it had joined the search for the missing jetliner on Malaysia's request, widening the net to an area near the Andaman Sea.

Vietnam said it had halted its air search and scaled back a sea search while it waited for Malaysia to offer more detail.

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

Asked about the claim that the plane had last been detected over the Strait of Malacca - suggesting it had crossed the entire peninsula - he replied: "We've asked Malaysian authorities twice but so far they have not replied to us.

"We informed Malaysia on the day we lost contact with the flight that we noticed the flight turned back west but Malaysia did not respond."

Malaysia's air force chief denied telling a local newspaper that on the day it disappeared the aircraft was last detected at 2.40am on the western coast of the Malay peninsula by a military radar - a detail confirmed to news agencies by at least one unnamed military official. That would mean the plane was known to be in the air more than an hour later than previously thought and had not only turned around but flown right across the peninsula - helping to explain why the search had expanded from the area between Malaysia and Vietnam to cover a large zone to the west.

In a statement Rodzali Daud said he had been asked whether the plane had been detected off the west coast and had merely reiterated that the flight might have turned back.
© Flight AwareThe last known position of Flight 370
Malaysia's head of civil aviation, Azharuddin Abdul Rahman, said he could neither confirm nor deny contact on the west coast, saying that the country was still investigating and looking at the radar readings. Confidence in the Malaysian authorities' transparency had hardly been helped by an eariler response when asked why crews were searching the Strait of Malacca: "There are some things that I can tell you and some things that I can't," Rahman said.

On Tuesday he described the disappearance as "an unprecedented mystery" in aviation.

It is possible that the military radar reading detected an object but that it cannot be identified conclusively as flight MH370.

On Wednesday, pressed by relatives of Chinese passengers on what information the military had given civil officials, the Malaysian government's envoy to China told them "now is not the time" to reveal it, Singapore's Straits Times reported.

He did disclose that the last words heard from the flight were "All right, good night." That was the crew's response to Malaysian air traffic controllers who had told them the plane was entering Vietnamese air space and air traffic controllers from Ho Chi Minh city would take over.

Deepening the confusion, Colonel Umar Fathur of the Indonesian air force told reporters that Malaysia had informed it the plane was above the South China Sea, about 10 nautical miles off Malaysia's east coast, when it turned back and then disappeared. That would place its last confirmed position around 110 nautical miles closer to Malaysia than previously thought.

Meanwhile Malaysian authorities have reportedly complained that Vietnamese officials have confused matters by issuing premature reports that they have found possible debris. In all cases the material has turned out to be unrelated.

Two-thirds of those on board the Boeing-777 were Chinese, and China has repeatedly urged Malaysia to speed up search efforts. Beijing has also been sending a growing number of ships and aircraft to assist. As public concern grows about the state of the operation, relatives have vented their frustration to Chinese officials.

The Washington Post cited one popular post that was forwarded thousands of times on Chinese microblogs: "Vietnam keeps discovering. Malaysia keeps denying. China keeps sending things on the way. Journalists keep waiting at the Lido hotel [where relatives are waiting]. Family members keep being in pain. .โ€‰.โ€‰. But where is the plane?"

The Telegraph reported that the United States Federal Aviation Administration had warned four months ago of a potential weak spot in Boeing 777s that could lead to a loss of structural integrity, but experts have maintained the aircraft has a strong safety record.