The trucks that were stranded were heading to northern Spain or central Europe, said Antonio Almeida, head of the Portuguese gendarmerie.

He said Portuguese authorities were only allowing through trucks travelling to Salamanca, Madrid or southern Spain.

A weather service official said the freezing temperatures recorded this week only occur once every 10 years.

The southeast Portuguese town of Sagres even set a record on Thursday with temperatures there dipping to 0 degrees Celsius (32 degrees Fahrenheit).