A ship searching for missing Malaysia Airlines Flight 370 "detected signals consistent with those emitted by aircraft black boxes," an Australian official announced Monday.
The Australian vessel Ocean Shield picked up the signals using a U.S. Navy towed pinger locator, but the signals have not been confirmed as being from the missing flight, Air Chief Marshal Angus Houston, the chief coordinator of the Joint Agency Coordination Center, said during a press conference in Perth, Australia.
Ocean Shield remains in the area, trying to regain contact with the signal, Houston said.
"Two separate signals have occurred within the northern part of the defined search area," he said. The first detection was held for about two hours and 20 minutes. The ship lost contact and then re-acquired the signal for 13 minutes.
Houston said, "this is a most promising lead," but cautioned that further confirmation was required and that it may be several days before officials can verify a connection to the missing plane.
"We haven't found the aircraft yet," he said.
Malaysian Transportation Minister Hishammudin Bin Hussein echoed Houston's sentiment, warning against "unconfirmed findings and making conclusions," but, he added, "we are cautiously hopeful that there will be a positive development in the next few days, if not hours."
Several steps still have to be taken before the signals can be confirmed as being from the missing flight. First, searchers need to fix the position of the signal. Then an unmanned underwater vehicle would attempt to locate wreckage on the sea floor.
"Another source, such as wreckage, would verify this lead," Houston said.
The area in which the signals were detected is approximately 14,750 feet deep. That depth is also "the limit of capability of the autonomous underwater vehicle," Houston said.
If wreckage from Flight 370 was confirmed, the recovery phase of the operation would begin.
The first signal was detected Saturday by a "black box detector" deployed by Chinese ship Haixun 01 in the Indian Ocean. The pulse was picked up around 25 degrees south latitude and 101 degrees east longitude, according to China's official news agency, Xinhua.
Sunday, Haixun 01 reported it had detected the signal again for 90 seconds within 1.4 miles of the original signal.
The Boeing 777, which had 239 people aboard, lost communication with civilian air controllers soon after it took off early March 8 from Kuala Lumpur International Airport in Malaysia. No emergency signals or distress messages were received before the jet vanished from radar.
Up to nine military planes, three civil planes and 14 ships will assist in Monday's search for the jet, according to the Joint Agency Coordination Center, and good weather is expected.
Contributing: Laura Petrecca and John Bacon; The Associated Press