China's official news agency is reporting what could be a breakthrough in locating the Malaysia Airlines jet missing for nearly a month.
A Chinese ship, searching about 1,600 kilometers northwest of Perth, Australia, says it heard multiple pings that could have come from the missing plane's flight recorder.
The Xinhua news agency reported the Chinese patrol ship Haixun 01 in the southern Indian Ocean detected a pulse signal on the frequency 37.5 kilohertz.
A Chinese Central Television (CCTV) reporter on board the ship, in a live broadcast, said the pings - one second apart - were detected by a hydrophone deployed from the vessel both Friday and Saturday.
China's Maritime Search and Rescue Agency is quoted by Xinhua as saying there is no confirmation that the pulse originated from the flight recorder, or "black box," of missing flight MH370.
The Chinese report was not immediately confirmed by authorities in China, Malaysia or Australia. But aviation experts in the United States and elsewhere say it is conceivable that such a signal could have come from the plane, which is presumed to have gone down at sea with the loss of all 239 people on board.
Search planes and boats have been crisscrossing a large area of the southern Indian Ocean off the western coast of Australia, where the plane is believed to have gone down. An analysis of some of the last known data signals from the jet, monitored by a satellite, pointed search teams to that remote stretch of ocean.
The search for signals from the Boeing 777's flight recorders has been intense during the past week, since the batteries powering the emergency beacons could be exhausted at any time.
A military ship from Australia and another from Britain, both equipped with underwater sensor technology, also began hunting for the black box signals on Friday.
Malaysian and Australian officials offered only pessimistic forecasts this past week, saying that, without any confirmed recovery of debris from the plane, the mystery of what happened may never be known.
Australia's prime minister has called the search for the plane the most complex such undertaking in history.
The plane disappeared during the early stages of a scheduled flight from Kuala Lumpur to Beijing, in the early hours of March 8.