By Keith Laing - 03/13/14 09:34 AM EDT
A Malaysia Airlines flight that has been missing since last Friday may have continued flying for several hours after it lost contact with air traffic controllers, The Wall Street Journal reports.
Air traffic controllers in Malaysia and nearby Vietnam have said they last heard from the airplane about one hour into its journey from Kuala Lumpur, Malaysia, to Beijing.
The Journal reports that the plane may have continued flying in an opposite direction for as long as four hours with its air traffic control radars turned off, however.
The search for the missing Malaysia Air flight has lasted six days.
The plane’s disappearance has sparked terrorism concerns, though U.S. and Malaysian officials have both said it is too early to determine causes for the incident.
The Malaysia Air plane was a Boeing 777 that was carrying 239 people at the time of its disappearance.
U.S. State Department officials have confirmed that at least three of the passengers who were on board the plane were American citizens.