CAIRO — Egypt said Wednesday that a French ship has picked up signals from deep under the Mediterranean Sea, presumed to be from one of the black boxes of the EgyptAir plane that crashed last month, killing all 66 passengers and crew on board.

The development raised hopes the plane’s flight data and cockpit voice recorders, known as the black boxes, could be retrieved and shed light on the aircraft’s tragic crash.

In Cairo, the Civil Aviation Ministry cited a statement from the committee investigating the crash as saying the vessel Laplace received the signals. The French Navy confirmed the Laplace arrived on Tuesday in the search area and picked up the signals “overnight.”

The signals’ frequencies could match with the frequencies of data recorders, a French Navy spokesman told The Associated Press. The location and identification of the source of the signals have not been determined yet, he said, adding that he searches are still at an “early stage.” He spoke on condition of anonymity because he wasn’t allowed to speak publicly on the issue.

Laplace’s equipment picked up the “signals from the seabed of the wreckage search area, assumed to be from one of the data recorders,” the Egyptian statement read. It added that a second ship, John Lethbridge affiliated with the Deep Ocean Search firm, will join the search team later this week.

Locator pings emitted by flight data and cockpit voice recorders, known as the black boxes, can be picked up from deep underwater. The Laplace is equipped with three detectors made by the Alseamar company designed to detect and localize signals from the flight recorders, which are believed to be at a depth of about 3,000 meters (9,842 feet) underwater.