Officials dismissed reports Thursday that the missing Malaysian airliner’s engines continued sending data for hours after its last contact, but said it was possible the plane continued flying and that they would widen their search farther to the west.

The Wall Street Journal newspaper quoted U.S. investigators on Thursday as saying they suspected the Boeing 777 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.

Malaysian Defense Minister and acting Transport Minister Hishammuddin Hussein 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., several minutes before the plane lost contact over the South China Sea on its way from Kuala Lumpur to Beijing.

An international search effort is sweeping the South China Sea, but also focusing on the Strait of Malacca because of unconfirmed military radar sightings indicating the plane may have changed course and headed west after it stopped communicating.

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 expanded into the Andaman Sea and that the country was asking for radar data from neighboring countries such as India. If the plane flew far from the current search areas, then locating it will likely be a vast task.

Investigators have not ruled out any possible cause for the disappearance of the plane and the 239 people on board. 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.

The plane was heading northeast over the Gulf of Thailand toward Vietnam when it vanished. The last message from the cockpit was routine: “All right, good night,” was the signoff transmitted to Malaysian air traffic controllers.

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.

The hunt has been punctuated by false leads, the latest Thursday when planes were sent to search the area where Chinese satellite images published on a Chinese government website showed “three suspected floating objects” of varying sizes in a 20-kilometer (12-mile) radius off the southern tip of Vietnam.

“There is nothing. We went there, there is nothing,” Azharuddin said.

In the latest in a series of confusing events, he later said the Chinese Embassy had notified the government that the images were released by mistake and did not show any debris from Flight 370.

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.

(AP)