(Fox News) -- China's official news agency says a Chinese ship that is part of the multinational search effort looking for the missing Malaysia Airlines plane has detected a "pulse signal" in southern Indian Ocean waters.
The report says a black box detector deployed by the vessel, Haixun 01, picked up a signal at 37.5Hz per second Saturday at around 25 degrees south latitude and 101 degrees east longitude.
The report said it was not established whether that the signal was related to missing Malaysia Airlines Flight 370.
The Australian government agency coordinating the search would not immediately comment on the report.
After weeks of fruitless looking, officials face the daunting prospect that sound-emitting beacons in the flight and voice recorders will soon fall silent as their batteries die after sounding electronic "pings" for a month.
Officials have said the hunt for the wreckage is among the hardest ever undertaken, and will get much harder still if the beacons fall silent before they are found.
Two ships -- the Australian navy's Ocean Shield and the British HMS Echo -- carrying sophisticated equipment that can hear the recorders' pings returned Saturday to an area investigators hope is close to where the plane went down. They concede the area they have identified is a best guess.
Up to 13 military and civilian planes and nine other ships took part in the search Saturday, the Australian agency coordinating the search said.
Because the U.S. Navy's pinger locator can pick up signals to a depth of 20,000 feet, it should be able to hear the plane's data recorders even if they are in the deepest part of the search zone -- about 19,000 feet. But that's only if the locator gets within range of the black boxes -- a tough task, given the size of the search area and the fact that the pinger locator must be dragged slowly through the water at just 1 to 5 knots (1 to 6 mph).