PERTH, Australia (AP) — The head of the coordinated search for Malaysia Airlines Flight 370 says crews will continue listening for faint sounds from deep in the Indian Ocean, like they heard on Saturday and Sunday.

Officials thought the signals could be from the jetliner's two data recorders, but they couldn't detect those sounds on Monday.

There's a fear that any pings from the plane's black boxes could die out at any time because the data recorders' batteries usually last about 30 days after a crash.