UPDATE: Australian search vessel Ocean Shield picked an electronic "ping" Sunday morning local time, authorities say - but in a different region, about 300 nautical miles from the area where a Chinese vessel detected possible signals from Flight MH370's cockpit voice recorder or flight data recorder.
Batteries in the two "black boxes" are due to run out any day.
Like the "accoustic events" picked up by Chinese patrol ship Haixun 1, it is not clear if the signals are from one of the MH370 black boxes. Whales and general shipping noise can cause false positives, says the Joint Agency Coordination Centre.
More sophisticated detection gear is being moved to the location of where Ocean Shield picked up the possible signal.
Flight MH370: Chinese pick up a ping
EARLIER: A Chinese patrol ship searching for Flight MH370 has recorded a pulse signal with the same frequency (37.5 kHz) as the lost Malaysian Airline's flight recorder, China state news agency Xinhua reports.
A black box detector deployed from the ship Haixun 01 picked up the signal on Saturday for around 90 seconds in the southern Indian Ocean search area. It also picked up a brief signal Friday.
The ping could only come from a human device, University of Western Australia oceanographer Professor Charitha Pattiaratchi told media.
‘If you look at the noise in the ocean and the particular frequencies in there, rain makes a different frequency, whales call at a different frequency. All of the different natural frequencies we know."
Anish Patel, president of pinger manufacturer Dukane Seacom, said that was the standard beacon frequency for both black boxes: the cockpit voice recorder and the flight data recorder.
However, neither is 37.5kHz exclusive to black boxes.
Australian Defence Minister David Johnston urged caution following a number of false leads in what has been an "emotional roller coaster" for those affected by the MH370 tragedy.
"I have not had a chance to get to the bottom of this but can I tell you this is not the first time we've had something that has turned out to be very disappointing," he told ABC24.
"The deployment of RAAF assets to the area where the Chinese ship detected the sounds is being considered."
Retired Air Chief Marshal retired Angus Houston, the head of the search's Joint Agency Coordination Centre, said the origins of the electronic pulse signals detected by the Chinese ship could not yet be verified by Australian authorities. He said white objects had also been sighted about 90 kilometres from the detection area and Australian authorities were considering sending Royal Australian Air Force assets to the area on Saturday night.
On Friday, as Mr Houston warned batteries on Flight MH370's recorders will run out within days, Australian search vessels deployed underwater sonar detectors, including a drone on loan from the US navy that can dive to 4500m.