The co-pilot of the missing Malaysian airliner is reported to have tried to make a mid-flight call from his cellphone just before the plane vanished from radar screens.
A report in the Malaysian newspaper New Straits Times says the call from Fariq Abdul Hamid's phone ended abruptly, possibly because the aircraft was moving swiftly away from the nearest telecommunications tower.
The report - headlined as a "desperate call for help" - does not say who he was trying to contact.
There have been unconfirmed previous reports in the Malaysian media of calls by the captain before or during the flight but no details have been released.
The country's transport ministry says it's examining the report and will issue a response.
No new acoustic signals have been detected in the past 24 hours in the search for flight MH370, which went missing on 8 March.
Hopes of recovering the aircraft's black box rose significantly after HMAS Ocean Shield detected four signals believed to have come from MH370's flight recorder.
However, the Joint Agency Coordination Centre said on Saturday morning that no new signals had been detected in the past 24 hours.
AAP reports nine military aircraft, one civil aircraft and 14 ships will continue the hunt on Saturday, visually searching an area measuring 41,393 sq km about 2300km northwest of Perth.
HMAS Ocean Shield will continue using a "towed pinger locator" device on Saturday to try to detect more acoustic signals.
The work is in conjunction with AP-3C Orion aircraft and HMS Echo.
"This work continues in an effort to narrow the underwater search area for when the autonomous underwater vehicle is deployed," the JACC added said.
Weather conditions in the search area are said to include 10-knot southeasterly winds and sea swells up to one metre.