The Hague: The Netherlands on Tuesday investigated the source of a massive telephone network breakdown that disabled the country's emergency numbers.
The disruption late Monday started with the KPN national network and then spread to linked providers across the country, lasting for four hours before it was fixed.
Police, firefighters and ambulance workers took to the streets so they could be contacted if necessary and the government issued alternatives to the 112 emergency hotline on social media.
Justice and Security Minister Ferd Grapperhaus summoned KPN's management on Tuesday to explain the breakdown and ensure that it will "not happen again." Grapperhaus tweeted that they must "carefully figure out how this malfunction could have arisen".
The Dutch national counterterrorism coordinator will also be involved in the meeting, local media said.
Hacking was however not believed to be the cause of the breakdown, senior KPN official Joost Farwerck told the Nieuwsuur programme on Monday evening.
Dutch media reported on Tuesday that KPN's chief executive Maximo Ibarra was going to step down, but said it was due to family matters and was not connected to the breakdown.
The phone outage came as the Netherlands was hit by a heatwave which also put extra strain on emergency services, with temperatures set to reach 36 degrees Celsius (97 Fahrenheit) in the south of the country.
Lawmakers in the lower house of parliament are also expected to raise the issue on Wednesday.
"It is quite incomprehensible that 112 seems so fragile," Chris van Dam, an MP from the centre-right CDA party, said on Twitter.
MP Arne Weverling of Prime Minister Mark Rutte's VVD party said that "whatever the reason, it shows how vulnerable we are." Separately, the major Dutch supermarket chain Albert Heijn said it had suffered an important breakdown at checkouts in stores across the country, its second in the space of a month.