Malaysian officials are denying U.S. investigators' report that Malaysia Airlines Flight 370 remained in the air for about four hours after it lost contact.
Hishammuddin Hussein, minister of defense and acting minister of transport, tweeted on Thursday that the situation was unprecedented and squashed claims that Malaysia had slowed its search for the missing Boeing 777.
Let me be clear, no real precedent for situation like this. The plane vanished. #MH370 @HishammuddinH2O
— H2O Comms (@H2OComms) March 13, 2014
According to The Wall Street Journal, U.S. officials believe flight 370 flew for a total of five hours, meaning that the plane, which was carrying 239 people, could have continued traveling for a substantial amount of time under conditions that still remain a mystery.
The international search effort continues nearly one week after Malaysia Airlines flight 370 dropped off the radar and vanished without any warning. Despite seemingly strong leads, the investigation has turned up no clues as to what happened to the jet.
See also: Missing Passengers' Phones Are Still Ringing. Can They Hear It?
On Wednesday, the story took an odd turn when an oil rig worker stationed off the southeastern coast of Vietnam claimed to have witnessed the crash. In a email sent to his employer, which ABC journalist Bob Woodruff acquired, the man says, "I believe I saw the Malaysian Airlines plane come down. The timing is right."
Vietnamese officials, however, said they found nothing in the water.
Hours later, Chinese State TV reported that it had new satellite images that showed debris from the plane. However, that turned out to be a false lead after a search team combed the area and found nothing.

The map above highlights the search area for the missing Malaysia Airlines flight. Noted on the map is the located of China's satellite images as well as the point at which the plane may have switched directions.
Authorities expanded the search area for the missing Malaysia Airlines plane to 27,000 square miles on Wednesday after the Malaysian military said flight 370 may have changed directions — citing a blip on its radar — and headed west before disappearing, prompting search teams to look in a whole new direction.
However, Malaysia Air Force Chief Gen. Rodzali Daud backpedalled the next day, saying he regretted his statement. This is partly why Phan Quy Tieu, Vietnam's vice minister of transportation, told reporters on Wednesday that the country was pulling back on its hunt until Malaysia had something solid to go on from here. So far, he said, the information provided is "insufficient." That same day, China pushed Malaysia harder to amp up its search, to which officials responded on Thursday defensively of their efforts.
Malaysia has nothing 2 hide. Spared no expense and effort. #MH370 @HishammuddinH2O
— H2O Comms (@H2OComms) March 13, 2014
But while Vietnam is scaling back, Japan and Indonesia are ramping up efforts. Eight members of a Japanese search team arrived in Kuala Lumpur on Wednesday to prepare for the arrival of two C-130 transport aircraft of the Air Self-Defense Force and two P-3C patrol planes of the Maritime Self-Defense Force. Indonesian authorities deployed its search mission over the Strait of Malacca as well.
Now, after six days of chasing dead-end leads, authorities remain at square one.

A man is silhouetted against a hazy sky at the viewing gallery in the Kuala Lumpur International Airport where posters and drawings with well wishes for the missing Malaysia Airlines jetliner MH370 are displayed, Thursday, March 13, 2014, in Sepang, Malaysia.
Image: Wong Maye-E/Associated Press
Malaysia Airlines flight 370 was at cruising altitude, around 35,000 feet, when it dropped from radar on March 7 with no signal from pilots, which is almost unheard of in the aviation world. Authorities believe it may have disintegrated in mid-flight, but no wreckage has been recovered after a widespread search. It's extremely rare for an aircraft to suddenly vanish, without warning, during cruising altitude, as most airplane accidents occur during takeoff or landing.

This map shows some of the more deadly plane crashes that have occurred as the result of an event that happened during cruising altitude. Click on the plane icons to expand the information. Note that the map is not a complete list.