Search teams detected a signal from the floor of the Java Sea on Friday but were not immediately able to discern if it was coming from the "black boxes" of the crashed AirAsia jet, officials said.
Divers were sent to the area but returned empty-handed, Indonesian armed forces chief Gen. Moeldoko said.
"We sent seven divers and they found some debris, but the black boxes were not there," Moeldoko, who has one name, told Indonesia's TVOne.
The "pinging" signal was detected about 300 yards from where the tail of the Airbus A320-200 was located on Thursday, but divers who examined the tail on Friday found that some parts were missing, Moeldoko said.
That raised the possibility that the black boxes -- containing the all-important flight data recorder and cockpit voice recorder, which are carried in the aircraft's tail -- were separated when Flight 8501 crashed into the waters off Borneo island on Dec. 28.
All 162 passengers and crew are believed to have died, but only 48 bodies have been recovered by search teams battling stormy seas during the wettest time of year in Indonesia. Thunderstorms are believed to have played a role in the crash but investigators say locating the recorders is crucial to determining exactly why the plane went down.
Moeldoko said sudden weather changes Friday forced search crews to halt an attempt to retrieve the tail using lifting bags, which would be strapped to the debris and inflated to bring it to the surface.
The work would resume later in the day if the weather allowed, he said.
Special correspondent Pathoni reported from Jakarta and staff writer Bengali from Mumbai India.
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