The co-pilot of missing Malaysian Airlines flight MH370 tried to make a call from his mobile phone just before it disappeared, it has been reported.
Malaysian newspaper The New Straits Times reported that investigators had traced the call to Fariq Abdul Hamid's phone and said it had ended "abruptly".
The paper said the plane was understood to have been flying low enough for a telecommunications tower to pick up the phone's signal at the time.
But it also quoted another source who warned there was no certainty a call had been made.
They told the paper Hamid's phone had been "detached", saying: "This is usually the result of the phone being switched off. At one point, however, when the airplane was airborne, the line was 'reattached'.
"A 'reattachment' does not necessarily mean that a call was made. It can also be the result of the phone being switched on again."
The paper reported it could not ascertain whom Hamid was trying to call.
The flight, which was carrying 239 people on board, disappeared on March 8 around an hour after it took off.
Earlier this week, UK air accident investigators said the data from the black box of another Malaysian Airlines plane had been been lost due to "unrobust behavior" after an incident where it had to return to Heathrow Airport due to equipment failures.
Investigators said all the Cockpit Voice Recording from that plane's blackbox were lost because it was left running after landing. The airline lacked robust procedures for ensuring the recordings were immediately preserved after a serious incident, they said.