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 missing Malaysia Airlines flight crew replied "All right, roger that" in its last communication before it went missing five days ago.
Malaysian authorities were forced to defend their handling of the operation to find the missing flight MH370 today as relatives expressed their anger at the lack of developments in the search.
Families' frustration at the lack of progress boiled over in Beijing when water bottles were thrown at officials.
Keir Simmons reports from Malaysia:
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.