Australian authorities say they are confident that underwater signals detected in the search for missing the Malaysian jetliner are from the airplane's black box recorders.
Australian Prime Minister Tony Abbott told reporters in Shanghai Friday that search crews looking for the plane have narrowed down that patch of Indian Ocean where they are searching for the sounds.
"We are confident that we know the position of the black box flight recorder to within some kilometers. But confidence in the approximate position of the black box is not the same as recovering wreckage from almost four and a half kilometers beneath the sea or finally determining all that happened on the flight," Abbott said.
Abbott briefed Chinese President Xi Jinping on the status of the search. Some two-thirds of the passengers onboard the flight were Chinese.
Pings consistent with a flight data recorder have been detected by an Australian ship that is using a U.S. naval device to detect black boxes.
Time is running out for authorities to locate the origin of the signals, since the batteries on the black box's locator beacon are set to run out after about 30 days.
The Malaysia Airlines jet, which was carrying 239 people, disappeared on March 8 while traveling from Kuala Lumpur to Beijing.
Malaysian authorities believe the plane was deliberately diverted and crashed into the sea. But without wreckage, many are skeptical.
If authorities can locate more pings, they plan to deploy a robot submarine to search the ocean floor.
Once the black box is retrieved, authorities will be able to determine what happened to the plane. Its fate has become one of the most puzzling mysteries in aviation history.