PERTH, Australia, April 7 -- Australian navy ship Ocean Shield detected suspicious signals consistent with aircraft black boxes, chief coordinator for the search of missing Flight MH370, said on Monday.

"The towed pinger locator deployed from the Australian defence vessel Ocean Shield has detected signals consistent with those emitted from aircraft black boxes," Angus Houston, former Australian defence minister who is heading the Joint Agency Coordination Center (JACC), told reporters.

Describing the new detection as "the most promising lead," Houston warned it has to be treated cautiously and responsibly until final determination is made.

He said after Ocean Shield, equipped with U.S. towed pinger locator, heard the suspicious signals, the next stop is to fix the position and attempt to locate wreckage.

"We cannot confirm until we find wreckage," he said, adding it may take some days for the confirmation.

Houston said the waters where new signals were detected have a depth of 4,500 meters, which makes it difficult to retrieve the black boxes, if they are lying on the ocean floor.

The new discovery was made in a sea area north of the place where Chinese vessel Haixun 01 picked up suspicious signals on Saturday, according to Houston, adding it remains unknown whether the two are related.