Almost three days after Malaysia Airlines flight MH370 went missing, officials from ten countries are still working around the clock. But they haven’t found any confirmed trace of the airplane or the 239 people who were on it. More than 40 ships and 34 planes are searching for debris in the Gulf of Thailand, which is a part of the South China Sea.

Malaysia Airlines

Malaysia’s Civil Aviation Authority head Azharuddin Abdul Rahman said that the disappearance of the plane is an “unprecedented aviation mystery.” The Malaysian Airlines plane took off at 1 a.m. Saturday (1 p.m. Friday ET) from Kuala Lumpur en route to Beijing. There were 227 passengers and 12 crew members. About two-third of the people aboard were Chinese, 38 were Malaysians, 7 Indonesians, 6 Australians, 5 Indians, 4 French and 3 Americans.

Loopholes in the work of Malaysia Airlines

China has asked Malaysia to step up the search efforts. As the search continues, questions mounted over a possible hijacking attempt, a bomb or security lapses. Earlier Sunday, a prominent Communist Party newspaper, The Global Times, issued a sharply worded statement. It said that there have been loopholes in the work of security authorities and Malaysia Airlines. Until Sunday, the Malaysian government could collect accurate information about passengers.

A promising lead emerged briefly after Vietnamese helicopters found a floating yellow object, which they thought might have been a life raft. But it turned out to be a dead end as the object was a “moss-covered cap of a cable reel.” Interpol said Sunday that two of the passengers used stolen passports, and it is investigating whether any others aboard had used false documents.

Did Malaysia Airlines plane break up mid-air?

Malaysia Airlines flight MH370 disappeared from radar screens about an hour after taking off from Kuala Lumpur. The plane had climbed to an altitude of 35,000 ft (10.67 kilometers) before it disappeared. The lost plane hadn’t sent any distress signal. It indicates that there could have been a sudden explosion or catastrophic failure. But Malaysian air force chief said that, according to data from radar tracking, it might have turned back from its planned route before it disappeared.

Another officer involved in preliminary investigations said that the airplane may have broken up mid-flight. That could have dispersed wreckage in a very large area, so debris would be difficult to find. When asked about the possibility of a bomb explosion, the official said there is no evidence of any such explosion yet. The United States reviewed images taken by its spy satellites to check for mid-air explosion. But U.S. authorities didn’t find any such evidence.

Passengers with stolen passports were not Asian-looking men

The Boeing 777 airliner has one of the best safety records. Its last fatal crash took place in San Francisco  on July 6, 2013 when three passengers died. The names of two Europeans, Italian Luigi Maraldi and Austrian Christian Kozel, appeared on the passenger manifest issued by Malaysia Airline, were traveling with stolen passports. They had lost their passports about two years ago in Thailand. Interpol said it checked all documents, and could see more “suspect passports.”

Malaysia’s home minister Ahmad Zahid Hamidi said the two Europeans with stolen passports were of Asian appearance. But Malaysian aviation officials later said that those two passengers with stolen passports were not “Asian-looking men”, according to a tweet by BBC.

Shares of Malaysia Airlines plunged about 20% on Monday to a record low.