TEHRAN, Young Journalists Club (YJC) - The bus carrying 55 people rolled down a steep hill after veering off the road on a bend east of Madeira's capital, Funchal, on Wednesday evening when it was still light and in fine weather.
Authorities said they are investigating the cause and would inspect the bus for mechanical problems.
Portuguese officials have not yet identified the victims by name or nationality, saying they are still collating information.
The bus was carrying German tourists, as well as a Portuguese driver and guide. People at the roadside are also thought to be among the casualties.
Tomasia Alves, head of the Funchal hospital, said authorities hope to have a list of victims by Saturday. She said the victims were roughly between 40 and 60 years old and included no children.
She said 28 people were taken from the accident scene to a morgue, and another person died later in hospital.
German Foreign Minister Heiko Maas said he was "deeply shaken by the tragic bus crash."
German Chancellor Angela Merkel expressed "sadness and shock" at the accident. "My sincere sympathy goes especially to all of the families who have lost their loved ones in this tragedy," she said.
Rescue services used two cranes before dawn Thursday to pull the bus, which was lying on its side with part of its roof torn off, from the crash site, local media reported.