Missing passenger's mobiles are still ringing?

In the information vacuum, any rumour, however wild or implausible, is leaped upon.

The accounts of some passengers on Chinese messaging tool QQ show they had been online, reports say, although the operator says that failure to shut the software down properly can give that impression.

Some have seized on Chinese press reports that relatives have heard ringing tones when trying to call their loved ones' mobile phones.

"This could be a clue and shouldn't be ignored," said a man from Beijing surnamed Chen, whose cousin was on board.

"The airline hasn't even been able to use technology to locate signals of the plane.

"Even if they could rule out the possibility that the phones were ringing, it would be better for relatives," he added.

"Then at least we wouldn't hold out any hope."

Meanwhile, some are still keeping hopes up.

"I hope it is a hijacking, then there will be some hope that my young cousin has survived," said a man in his 20s surnamed Su.

Families and friends of many of the 153 Chinese passengers -- more than two-thirds of those on board the flight to Beijing -- are gathered at the Lido Hotel in the city, waiting for news.

"My uncle and aunt had an emotional breakdown, they are not eating, drinking and sleeping and could not face coming here," said Su.

"They need our help. We have been telling them lies -- stressing the few positives in all of this -- to keep their spirits up."

Malaysia Airlines has offered to fly two relatives of each of the missing to Kuala Lumpur to be closer to the search, but Su said the family were worried for the welfare of his cousin's grief-stricken parents if they made the trip alone.

"We have offered to pay for ourselves, so the wider family can help our aunt and uncle," he said.

Inside the hotel ballroom, family members sitting in rows of seats watch a plasma television screening continuous news.

In the days since the Boeing 777-200 vanished from radar screens there have been repeated reports of oil slicks being found and possible debris sightings, only for each of them to be later ruled out.

"The wait has been absolute torture," said a man in his 20s surnamed Liu, from the northern city of Tianjin, who said his older brother was on the flight.

"We seemed to have been slowly fed information, which is making things a lot worse," he added.

Others are angry. Reports say that passengers confronted government officials at a meeting on Monday, and a man from Beijing whose brother was on board told AFP: "The government finally turned up, but it remains to be seen what they will do."

Another man called Tang said: "They have been very slow with information. Very slow. How difficult is it in this age to find a plane?"

A woman from Shandong province, who was being comforted by her sister, said furiously: "It is all about the people -- the people on the plane. We just want them back."

Emotions ran high as families broke for lunch, with one irate relative venting fury at Malaysia Airlines staff for asking him to see a meal ticket.

"Do you think that Malaysian food is delicious or what?" the man said, waving his arms around in a rage.

"This is the attitude of Malaysia Airlines towards the relatives. Your responsibility is to comfort people. Not to stop them and ask them for their ticket."