The hackers were able to access a Portuguese media conglomerate's email and text message system.
Hackers have targeted one of Portugal's leading media conglomerates to send fake news alerts.
Some of the most websites of Grupo Impresa were taken down in the cyberattack, which aimed to disrupt the company's services.
The online hack -- which occurred early on 2 January -- was reportedly carried out by a group calling itself 'Lapsus$'.
Subscribers to Grupo Impresa also received false news alerts including one that said: "Breaking: President removed and accused of murder: Lapsus$ is Portugal’s new president".
Grupo Impresa said in a statement that the hackers had been able to send emails and text messages from the media group but didn’t demand any payment.
The hackers accessed some subscriber information, but Impresa said it had no evidence they got hold of customers’ passwords or credit card details.
Grupo Impresa later regained control of its cloud services that day, although two of its main websites continued to use temporary sites.
The incident is being investigated by Portuguese police and the country’s National Cybersecurity Centre.