Portuguese President Marcelo Rebelo will attend a mass on Friday in tribute to 29 German tourists who died when their bus tumbled down a slope and crashed into a house on the tourist island of Madeira.
Investigators are still trying to determine how the vehicle ended up mangled on the side of a hillside near the town of Canico on Wednesday.
Portuguese public TV RTP reported on Friday that the bus's accelerator was possibly stuck and that the driver might have tried to stop the speeding vehicle by hitting a wall.
"I think the brakes were gone, I cannot imagine another reason (for the crash)," a 60-year-old German holidaymaker who escaped with a broken rib told Portuguese television.
Sixteen wounded people, of which 14 are German, remain in medical care in the regional capital Funchal, according to an update by the hospital, but none would be evacuated from the island on Friday.
"They are all in a stable condition," said the deputy clinical director of the hospital, Miguel Reis.
An aircraft intended to repatriate the victims has been "put on hold", the German foreign ministry told AFP, but will be used later to transport the wounded to Germany.
Most of the dead were aged in their 40s and 50s, according to local authorities.
They were among the more than one million tourists who visit the Atlantic islands off the coast of Morocco each year, attracted by their subtropical climate and rugged volcanic terrain.
President Rebelo will visit survivors in hospital on Friday before attending the mass at the Presbyterian church in Funchal.