According to a source from the Lisbon District Relief Operations Command (CDOS) and reported by Notícias ao Minuto the evacuation was down to a malfunction with the alarm system.

Contacted by Notícias ao Minuto, IKEA Portugal explained that normality was restored quickly - between 5 and ten minutes -, and guaranteed that it was a malfunction.

"The fire alarm went off, but it was a system error", assured the same source, explaining that the situation is being investigated.