People in Utrecht were left confused and alarmed on Monday morning after air-raid sirens were accidentally set off during a test.

The sirens were sounded in the city of Utrecht as well as Houten, Marssen and Amersfoort, at 11am. Engineers working on one pylon mistakenly set the entire local network off at once, Utrecht safety board said.

Ten minutes later board officials said there was no cause for alarm, but by then hundreds of people had posted concerned messages on social media.

All 4,000 sirens are tested at noon on the first Monday of every month. The government had planned to switch off the network at the start of 2020, but it was unable to come up with a reliable system of mobile phone alerts.

Ondertussen op het provinciehuis in Utrecht:

Bert, waar is deze rode knop eigenlijk voor?
– Geen idee Willem, nooit gezien ook.
Wil toch graag weten wat hij doet Bert.
– Moet je niet gewoon drukken dan?

#Luchtalarm pic.twitter.com/D4i99V00zT

— Kees Dorresteijn (@KeesvandeRadio) August 16, 2021