Military radar indicates that the missing Boeing 777 jet turned back before vanishing, Malaysia's air force chief said Sunday as authorities were investigating up to four passengers with suspicious identifications who may have boarded the flight.
The revelations add to the uncertainties surrounding the final minutes of flight MH370, which was carrying 239 people when it lost contact with ground controllers somewhere between Malaysia and Vietnam after leaving Kuala Lumpur early Saturday morning for Beijing.
A massive international sea search has so far turned up no trace of the plane, which lost contact with the ground when the weather was fine, the plane was already cruising and the pilots didn't send a distress signal _ unusual circumstance for a modern jetliner operated by a professional airline to crash.
Vietnamese air force jets spotted two large oil slicks Saturday, but it was unclear if they were linked to the missing plane, and no debris was found nearby.
Air force chief Rodzali Daud didn't say which direction the plane might have taken or how long for when it apparently went off route.
“We are trying to make sense of this,'' he told a media conference. ``The military radar indicated that the aircraft may have made a turn back and in some parts, this was corroborated by civilian radar.''
Malaysia Airlines Chief Executive Ahmad Jauhari Yahya said pilots were supposed to inform the airline and traffic control authorities if the plane does a U-turn. ``From what we have, there was no such distress signal or distress call per se, so we are equally puzzled,'' he said.
Two-thirds of the jet's passengers were Chinese. The rest were from elsewhere in Asia, North America and Europe.
After more than 30 hours without contact with the aircraft, Malaysia Airlines told family members they should ``prepare themselves for the worst,'' Hugh Dunleavy, the commercial director for the airline told reporters.
Authorities were checking on the suspect identities of at least two passengers who appear to have boarded with stolen passports. On Saturday, the foreign ministries in Italy and Austria said the names of two citizens listed on the flight's manifest matched the names on two passports reported stolen in Thailand.
This, and the sudden disappearance of the plane that experts say is consistent with a possible onboard explosion, strengthened existing concerns about terrorism as a possible cause for the disappearance. Al-Qaida militants have used similar tactics to try and disguise their identities.