Search and rescue operations for the missing plane for the past six days have been focused in the South China Sea and the Malacca Strait.

The search for a missing Malaysia Airlines passenger jet on Friday expanded westwards towards the Indian Ocean, amid new information gathered by US investigators that the aircraft may have flown for hours after it dropped off the radar.

Broadcaster CNN reported that the USS Kidd was heading from the South China Sea to the Indian Ocean to conduct a search for the Boeing 777-200 aircraft carrying 239 people.

Search and rescue operations for the missing plane for the past six days have been focused in the South China Sea and the Malacca Strait.

A statement by the US Pacific Command Thursday confirmed that the USS Kidd would proceed to the Straits of Malacca to help search for Beijing-bound flight MH370, which disappeared about an hour after it took off from the Kuala Lumpur early Saturday.

"Detailed information on Kidd's assignment in the Strait of Malacca is not immediately available," it said.

The Pacific Command said a maritime surveillance aircraft, the P-8A Poseidon, would also join the search. White House spokesman Jay Carney said late Thursday that investigators had received "new information," and Washington would discuss the redeployment of boats and aircraft with its partners.

There was no immediate reaction from the Malaysian authorities. Transport Minister Hishammuddin Hussein on Thursday said Malaysia would "spare no expense and no effort" to locate the missing plane.

Following reports in The Wall Street Journal casting doubts on the plane's last known location, the same newspaper reported later Thursday that communication satellites had received intermittent data "pings" from the missing plane, with the last "ping" being several hours after it disappeared off radar.

"The final satellite ping was sent from over water, at what one of these people called a 'normal' cruising altitude," the WSJ report said, quoting "people briefed on the matter."

The Malaysia authorities had described the earlier WSJ reports as "inaccurate."

Following an earlier lead concerning two passengers travelling on the flight on stolen passports, Thailand has placed an Iranian man who allegedly booked the mens' tickets on its wanted list, news reports said Friday.

Alireza Kolmoham was identified as having booked the tickets for two Iranians who were using passports which had been lost in Thailand by Italian and Austrian tourists, the Bangkok Post reported.

The two Iranians are not thought to be linked to the disappearance of the plane.