CANBERRA, May 29  -- The Joint Agency of Coordination Center (JACC) for the search of the missing Malaysian airline flight MH370 announced on Thursday that about 850 square kilometers of ocean floor searched by the autonomous underwater vehicle Bluefin-21 can now be discounted as the final resting place of the ill-fated aircraft.

JACC said in a press release on Thursday that Bluefin-21 completed its last mission on Wednesday afternoon. The autonomous vehicle has been searching areas defined by four acoustic signals detected in early April by the Towed Pinger Locator deployed from Australian naval ship Ocean Shield.

Those four pings were thought to come from the "black box" of the Malaysian aircraft.

The data collected by Bluefin-21 on its mission on Wednesday has been analyzed and no signs of aircraft debris have been found by the autonomous underwater vehicle since it joined the search effort in mid April.

So far, Bluefin-21 has searched over 850 square kilometers of the ocean floor. Ocean Shield departed the search area Wednesday night and is expected to arrive at Fleet Base West on Saturday.

"The Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgement, the area can now be discounted as the final resting place of MH370," the JACC statement said.

Earlier, U.S. broadcaster CNN quoted U.S. Navy's deputy director of ocean engineering Michael Dean as saying that there was now broad agreement that the signals came from some other man- made source unrelated to the jet that disappeared on March 8 carrying 239 people.

The U.S. Navy has since issued a statement calling Dean's comments "speculative and premature". JACC was reached by Xinhua but offered no comment on Dean's remarks.