Beijing, Mar 11 (The Hindu): Rescuers on Tuesday widened the search area for the missing Malaysia Airlines jet after it emerged that the Boeing 777 had possibly flown hundreds of kilometres west across Malaysia up to the Malacca Straits following its last radar contact.

Malaysian military officials said the aircraft changed course away from its planned route north towards Beijing near Kota Bharu, where it last made contact, and then "took a lower altitude".

The Boeing then may have flown west, reaching as far as the Malacca Strait off Malaysia's western coast, around 500 kilometres away from where the plane was earlier thought to have disappeared, military officials told Reuters.

The new revelation came on the fourth day of search operations, as aircraft and vessels from eight countries continued to unsuccessfully scour the Gulf of Thailand and the South China Sea northeast of the country, and began to expand the search into the Malacca Straits.

The Malaysian government said earlier the aircraft, with 239 people on board, had disappeared from civilian air traffic control at 1.30 am Saturday local time, around 50 minutes after taking off from Kuala Lumpur.

Military radars, however, detected the airplane one hour later, at 2.40 am, Malaysian Air Force chief Rodzali Daud told local media, raising the possibility that the plane, which had not sent any distress signal, had flown west with its transponders turned off following its last contact with civilian air traffic control an hour earlier.

The development came as officials said the two passengers on board with stolen passports were likely not linked with terror groups and were Iranian migrants, aged 18 and 29, seeking asylum in the West.

The Malaysian police chief said the two were likely "trying to migrate to Germany". The Iranian government said it would offer assistance with the Malaysian investigation into the stolen passports.

On board flight 370 were 154 Chinese, five Indians, 38 Malaysians, seven Indonesians, six Australians and travellers from the United States, France and half a dozen other nations. Some of the passengers' relatives, including 9 Chinese and three Indians who have waiting desperately in Beijing for news of their loved ones, travelled to Kuala Lumpur on Tuesday morning.