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.
Malaysian Transport Minister Mishamuuddin Hussein has told reporters the disappearance of flight MH370 is "unprecedented".
He said: "Our focus has been on finding the aircraft and we have not done anything that would jeopardise this search effort...Malaysia has nothing to hide."
He added: "There is no precedent for this. The plane vanished."
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.