KUALA LUMPUR - The search area for Malaysia Airlines flight MH370 has expanded further east of South China Sea and west into the Indian Ocean, Malaysia's Acting Transport Minister Hishammuddin Hussein said, while refusing to confirm reports that the missing plane may have flown over the Indian Ocean.

"The aircraft is still missing, and the search area is expanding," said Mr Hishammuddin. "Together with our international partners, we are pushing further east into the South China Sea and further into the Indian Ocean."

A multi-nation team involving 13 countries, 57 ships and 48 aircraft have been scouring the South China Sea where the plane was last seen on radar early Saturday, as well as the Strait of Malacca. The search expanded to the west of Peninsular Malaysia after Malaysian military radar showed an unidentified blip that suggested the plane might have turned back.

The hunt spread to the vast Indian Ocean on Friday after the White House cited "new information" that it might have flown for hours after vanishing nearly seven days ago.

Multiple US media reports, citing US officials, said the Boeing 777's communication system continued to "ping" a satellite for a number of hours after it disappeared off radar with 239 people aboard, en route from Kuala Lumpur to Beijing.

On this, Mr Hishammuddin said: "The investigation team will not release information until properly verified."

He added that Malaysia has checked with Boeing and Rolls Royce, makers of the plane and engine, and that reports that the missing plane flew for more than four hours after last reported location was "not true".

Reuters, citing sources familiar with the investigation, also reported on Friday that military radar-tracking evidence suggests the missing plane was deliberately flown across the Malay peninsula towards the Andaman Islands, a chain of isles between the Andaman Sea and the Bay of Bengal.

Despite the report, Mr Hishammuddin insisted that the main reason for widening the search field was the failure to locate the plane in the areas searched

"A normal investigation becomes narrower with time," he said. "But this is not a normal investigation. In this case, the information we have forces us to look further and further afield."

Mr Hishammuddin also said he could not confirm that there was no hijacking.

"We are investigating all possibilities," he said.

Mr Azharuddin Abdul Rahman, head of the Civil Aviation Authority, told the same press conference that Malaysia is working with US investigators to establish if there is any satellite information that could help locate the airliner.

"They indicated they were studying the possibility of satellite communication. Whatever they have and will share with us," he told reporters.