Beijing -

No evidence has been found linking the 153 Chinese passengers aboard the missing Malaysia Airlines flight to terror or hijacking, state media said Tuesday, citing Beijing's envoy in Kuala Lumpur.

China's ambassador to Malaysia, Huang Huikang, also said China

had begun searching for the aircraft on its own territory amid a huge international search operation covering vast areas north and south of the plane's last-known position.

A criminal investigation had been launched, Huang said, but added that some information could not yet be revealed.

“The probe into the incident's cause is not suitable to be conducted in a high-profile way,” he said, according to Xinhua.

Huang said background checks on all passengers from the Chinese mainland on board missing flight MH370 did not find any evidence that they were linked to a hijacking or terrorist attack on the jet, the official Xinhua news agency reported.

After taking off from Kuala Lumpur heading to Beijing, the jet disappeared on March 8 with 239 people on board.

Twenty-six countries are now helping to hunt for the plane after satellite and military radar data projected two huge corridors through which the plane might have flown.

The northern route stretches in an arc over south and central Asia, passing across far western China, including Xinjiang and Tibet.

Discontent among ethnic minorities complaining of repression in the two regions has led, respectively, to violent attacks by Uighurs and to self-immolations by Tibetans.

The southern corridor swoops deep into the southern Indian Ocean west of Australia.

The investigation has zeroed in on the plane's captain, Zaharie Ahmad Shah, and his co-pilot Fariq Abdul Hamid, with a key question being who was in control of the aircraft when it veered off course about an hour into its flight.

“The Malaysian government has been doing its best in search and investigation, but it lacks experience and capability to handle this kind of incident,” Huang said, according to Xinhua. - Sapa-AFP