SURABAYA, Indonesia — The mystery of Indonesia’s missing airliner was partly solved on Tuesday, when rescue teams retrieved and tallied a grim inventory of bodies and debris from the plane off the coast of southwestern Borneo.

But it remained unknown what caused the plane, AirAsia Flight 8501, to plunge into the sea on Sunday, less than an hour after leaving Surabaya for Singapore.

Although Indonesian officials did not say so explicitly, their comments on Tuesday suggested that it was unlikely that survivors would be found.

“I am so very sorry for this accident,” Joko Widodo, Indonesia’s president, said before meeting with families of passengers here. “I hope families can stay strong while facing tragedy.”

Throughout the afternoon, the Indonesian authorities built up an inventory of debris collected by ships and helicopters from the sea surface, including life vests, aircraft parts and what appeared to be a small blue suitcase. Indonesian television showed a rescuer descending from a helicopter toward a corpse, which, like other bodies found, was not wearing a life jacket.

And Bambang Soelistyo, the head of Indonesia’s National Search and Rescue Agency, said more bodies had been retrieved from the Java Sea early Wednesday, including one of a woman in a flight attendent’s uniform. Further search efforts were hampered by foul weather, he added.