The co-pilot of missing Malaysian airliner flight MH370 attempted to make a mid-flight call from his mobile phone just before the plane vanished from radar screens, a report said citing unnamed investigators.

The call ended abruptly possibly "because the aircraft was fast moving away from the (telecommunications) tower", New Straits Times quoted a source as saying.

But the Malaysian daily also quoted another source saying that while Fariq Abdul Hamid's "line was reattached", there was no certainty that a call was made from the Boeing 777 that vanished on March 8.

The report — titled a "desperate call for help" — did not say who he was trying to contact.

Fariq and Captain Zaharie Ahmad Shah have come under intense scrutiny after the plane mysteriously vanished en route from Kuala Lumpur to Beijing with 239 people on board.

Investigators last month indicated that the flight was deliberately diverted and its communication systems manually switched off as it was leaving Malaysian airspace, triggering a criminal investigation by police that has revealed little so far.