Search teams looking for the flight recorders of the EgyptAir plane have picked up a radio signal from an emergency locator transmitter, Egyptian investigators say.
This could help to narrow the search area for the “black boxes” to a 5km (3 mile) radius in the Mediterranean Sea.
A deep-water operation will start in the coming days, French officials said.
All 66 people on board Flight MS804 were killed when the plane disappeared not far from its destination on 19 May.
The Airbus A320 was flying overnight from Paris to Cairo when it vanished from Greek and Egyptian radar screens, apparently without having sent a distress call.
The signal detected was from a device situated in the rear of the cabin on the plane which transmits its location, Egypt’s chief investigator, Ayman al-Moqadem, said.
This part of the fuselage is near the tail, where the “black boxes” are located.
But the signals detected are different from those emitted by the flight recorders.
France’s BEA air safety agency said a French naval ship specialised in underwater searches would join the operation to find the recorders.
On Thursday, hundreds of people gathered in Cairo for a candlelit vigil for the victims of the crash.
Among those on board MS804 were 30 Egyptians, 15 French citizens, two Iraqis, two Canadians and citizens from Algeria, Belgium, Britain, Chad, Portugal, Saudi Arabia and Sudan.
They included a boy and two babies as well as seven crew and three security staff.
Debris from the plane has been recovered from the sea, some 290km (180 miles) north of the Egyptian port city of Alexandria.
Egypt’s president has said that “all scenarios are possible”, but Civil Aviation Minister Sherif Fathy said last Friday that a terrorist attack was more likely than a technical failure.
Greece’s defence minister said last week that, after leaving Greek airspace and before it disappeared from Greek radar, the plane abruptly turned 90 degrees left and then 360 degrees to the right, dropping from 11,300m (37,000 ft) to 4,600m (15,000ft) and then 3,000m (10,000ft).
The Aviation Herald also reported that the plane sent a series of warnings indicating that smoke had been detected on board three minutes before it disappeared.
The warnings do not indicate what might have caused the smoke.