KUALA LUMPUR, Malaysia >> Malaysian authorities expanded their search for the missing jetliner into the Andaman Sea and beyond on Thursday after saying it could have flown for several hours after its last contact with the ground.

That scenario would make finding the jetliner a vastly more difficult task, and raises the possibility that searchers are currently looking in the wrong place for the Boeing 777 and its 229 passengers and crew. 

In the latest in a series of false leads, planes were sent Thursday to search an area where Chinese satellite images published on a Chinese government website reportedly showed three suspected floating objects off the southern tip of Vietnam. 

They saw only ocean.

“There is nothing. We went there, there is nothing,” said acting Malaysian Transport Minister Hishammuddin Hussein. 

Compounding the frustration, he later said the Chinese Embassy had notified the government that the images were released by mistake and did not show any debris from Malaysia Airlines Flight MH370. 

The plane was flying from Kuala Lumpur to Beijing early Saturday when it lost contact with ground controllers and civilian radar. 

An international search effort is sweeping the South China Sea and also the Strait of Malacca because of unconfirmed military radar sightings that might indicate the plane changed course and headed west after its last contact.

The Wall Street Journal newspaper quoted U.S. investigators on Thursday as saying they suspected the plane remained in the air for about four hours after its last confirmed contact, citing data from the plane’s engines that are automatically transmitted to the ground as part of a routine maintenance program.

Hishammuddin said the government had contacted Boeing and Rolls Royce, the engine manufacturer, and both said the last engine data was received at 1:07 a.m., around 23 minutes before the plane lost contact.

But asked if it were possible that the plane kept flying for several hours, Hishammuddin said: “Of course, we can’t rule anything out. This is why we have extended the search.”

He said the search had been widened into the Andaman Sea and Malaysia was asking for radar data from neighboring countries. India plans to deploy air and sea assets in the southern section of the sea, a senior official said on condition of anonymity because he was not authorized to speak to the media. 

Investigators have not ruled out any possible cause for the disappearance of the plane.

Experts say a massive failure knocking out its electrical systems, while unlikely, could explain why its transponders, which identify it to civilian radar systems and other planes nearby, were not working.  Another possibility is that the pilot, or a passenger, likely one with some technical knowledge, switched off the transponders in the hope of flying undetected.

The jet had enough fuel to reach deep into the Indian Ocean.

Dozens of ships and aircraft from 12 nations have been searching the Gulf of Thailand and the strait, but no confirmed trace has been found. The search area has grown to 35,800 square miles (92,600 square kilometers), or about the size of Portugal.

Experts say that if the plane crashed into the ocean then some debris should be floating on the surface even if most of the jet is submerged. Past experience shows that finding the wreckage can take weeks or even longer, especially if the location of the plane is in doubt.

Malaysia’s air force chief said Wednesday that an unidentified object appeared on military radar records about 200 miles (320 kilometers) northwest of Penang, Malaysia, and experts are analyzing the data in an attempt to determine whether the blip is the missing plane.