A Portuguese train with at least 50 people on board derailed, a spokeswoman for the train operator said, and SIC television said some passengers were injured.
"There was a derailment," the spokeswoman said, adding that the accident was in the Douro valley region but she had no further information due to difficult access to the area.
Lusa news agency reported that some of the passengers had been taken to hospital. SIC television said several people were injured and some were trapped in the wreckage.