"At the end of this morning, 22 October, NOS suffered a failure in its mobile network, with an impact on customers in some areas of the country, in voice and data services,” the operator said in a statement, ensuring that the services are now fully restored.

In a statement, the company said that the NOS teams worked flat out with their partners, to recover all functions as quickly as possible to minimise the impact on their customers.

The company added that the causes of this serious incident will be the subject of an investigation and the results will be made known.

The operator had activated contingency plans on Tuesday due to a communications failure.

During the morning, NOS' official source confirmed to Lusa a failure in its mobile network, with an impact on customers in some areas of the country, in voice and data services.

NOS regrets the inconvenience that this situation may have caused to the affected customers, the statement said.