An "electronic ping" was picked up from the Malaysia Airlines flight by satellites after the plane lost contact with ground control, Reuters reports. Meanwhile, US officials have been given an "indication" the plane crashed into the Indian Ocean.
The response to the search for the missing Malaysian Airlines jet from neighbouring countries and international agencies has been "overwhelming", the Malaysian acting transportation minister has said.
Hishammuddin Hussein said coordinating the search effort had not been easy, but revealed the situation was now "moving very, very fast".
"Let us pray that we get some more positive results in the near future," he added.
The minister also warned the media against publishing any unverified information to avoid causing distress to the families of the 239 missing passengers.
A mother has described her frustration as she waits for answers on the fate of her missing son who is on board the missing Malaysia plane.
Malaysia's military believes a jetliner missing for almost four days turned and flew hundreds of kilometres to the west.
The wife of a passenger travelling on the missing Malaysia Airlines flight has spoken of her struggle to cope as she waits for news.