The missing Malaysia Airlines Flight still remains a mystery but officials have found that the plane sent signals to a satellite for four hours after it lose communications, showing that it could have flown hundreds of miles or more.

It has been six days since Flight MH370 disappeared with 239 people on board. Malaysian officials have since expanded their search toward India as the flight could have flown on for several more hours after it took off from Kuala Lumpur, the Associated Press reports.

Other clues have yet to lead officials to the aircraft.

"MH370 went completely silent over the open ocean," Malaysia's acting Transport Minister Hishammuddin Hussein told AP. "This is a crisis situation. It is a very complex operation, and it is not obviously easy. We are devoting all our energies to the task at hand."

The U.S. officials who said the plane was sending signals to the satellite said that the Boeing 777-200 wasn't transmitting data to the satellite, but was instead sending out a signal to establish contact.

The aircraft producer has a satellite service that can pick up data during the flight on how the aircraft is functioning which is relayed to the plane's home base. This is to provide information on if the plane will need maintenance when it lands. Malaysia Airlines wasn't using this service but it still had the ability to connect to the satellite and had been sending pings for hours.

"It's like when your cellphone is off but it still sends out a little 'I'm here' message to the cellphone network," the official told AP. "That's how sometimes they can triangulate your position even though you're not calling because the phone every so often sends out a little bleep. That's sort of what this thing was doing."

The plane was carrying enough fuel to continue flying for four hours. The official also said that messages from another data service were also received for a short time after the plane's transponder stopped working.

Original thoughts that the plane disintegrated during flight or suffered a catastrophic failure may be less likely as the pings to the satellite, data messages and the transponder would have stopped working all at the same time if this had happened.

The extend of the search has expanded significantly and the search area is now covering 35,800 square miles.

Hishammuddin did not rule out that the plane could have continued flying for hours.

 "Of course. We can't rule anything out. This is why we have extended the search. We are expanding our search into the Andaman Sea," he told AP.