The German, French and Spanish leaders have arrived together in the French Alps to visit the scene where a Germanwings planecrashed on Tuesday, killing all 150 on board.
Angela Merkel, Francois Hollande and Mariano Rajoy were briefed on the rescue and thanked the workers.
One of the "black box" recorders has been recovered at the site near Digne.
The Airbus A320 - flight 4U 9525 - from Barcelona to Duesseldorf crashed after an eight-minute rapid descent.
Germanwings chief Thomas Winkelmann said 72 of the 144 passengers were German citizens and 35 were Spanish, although the list was being constantly updated. The German victims included 16 pupils returning from an exchange trip.
UK Foreign Secretary Philip Hammond confirmed that three Britons were on board. Other victims were from Australia, Argentina, Iran, Venezuela, the US, the Netherlands, Colombia, Mexico, Japan, Denmark and Israel.
The plane's cockpit voice recorder - recovered by a helicopter team on Tuesday - was damaged but could still provide information, French Interior Minister Bernard Cazeneuve said.
Transport Minister Alain Vidalies said if voices had been recorded the investigation would proceed "fairly quickly". Investigators are still searching for the second "black box" - the flight data recorder.