The Netherlands was briefly in a state of emergency on Monday as around 12 million people across the country received an NL-Alert message on their mobile phones.
The alert system is used by the Dutch government to inform citizens about disasters and life-threatening situations in their area and provides emergency instructions.
The message also appeared on digital advertising signs and public transit departure boards, accompanied by an air alarm.
But while citizens may have been alarmed by the warning, Dutch authorities had already confirmed that it was just a routine test of the system.
The last time the public warning system was tested was in June when approximately 11.7 million people aged 12 and older received the text message. This was approximately 78 % of the country's population.
The NL-Alert control message was also shown for the first time on digital advertising screens in June.
The Dutch government has confirmed that those people who had their phones set up correctly would have received the message. Smartphone owners who did not may have also an empty battery or no phone signal.
Some other users may have decided to intentionally turn alerts off because the warning system may negatively impact a device's battery life.
The Ministry of Justice confirmed on Twitter that it was looking into which resources were most effective.
Greece, Lithuania and Romania are among other European countries using a phone alert system to warn citizens of emergency situations.
In 2018, the European Union also adopted a new Directive for all member states to set up a public warning system by 21 June 2022.