(CNN) At least 28 people are dead and another 28 are injured after a tour bus crashed on Portugal's Madeira Island.

Most of the casualties were German, Carmo Silva, a press officer for the Regional Health Department told CNN. In total, 56 people were on board the bus when it crashed, she said.

Claudia Veloso, a spokeswoman for Portugal's Interior Minister, confirmed that 28 people had died.

"The German Embassy in Lisbon is talking to local authorities and there possibly are German fatalities, but we cannot confirm at this moment," a German Foreign Ministry spokesperson told CNN.

According to Silva, the bus was going down a steep road, when it lost control and went down a cliff. The cause of the crash was not yet clear, she said.

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