HONG KONG — The search area in the Indian Ocean that recovery teams have been scouring for more than a month is probably not the final resting place of a missing Malaysia Airlines jetliner, the Australian task force in charge of the operation said Thursday.

A United States Navy underwater vehicle has been searching the ocean floor in an area west of the Australian continent since early April, after the detection of pings from what was then believed to be the black box recorders of Malaysia Airlines Flight 370.

The announcement followed comments made to CNN by Michael Dean, a United States Navy official, on Wednesday, who said the pings detected in early April were probably not from the black boxes, and could have in fact been from the search ships themselves or the underwater craft. Mr. Dean, the Navy’s deputy director of ocean engineering, told CNN that the search team’s best theory was that the pings “were likely some sound produced by the ship” or “within the electronics of the towed pinger locator.”