More than 70 passports belonging to Moroccan nationals, some containing visas for the Netherlands, have been stolen while being transported across Morocco.

Newspaper Assabah says the security services are on ‘the highest alert’ following the theft. They are concerned that the passports, which were being shipped by a courier company, may have ended up in the hands of criminals or terrorists, the Volkskrant reported.

The visas had been extended by the honourary consul in Rabat and were being taken to the north east of the country by the courier firm. The transport included other secret documents but these were left untouched, the Volkskrant said.

A spokesman for the Dutch foreign affairs ministry confirmed the theft and said 41 of the 71 passports contained a valid visa. The other requests had been rejected. The visas entitle the passport holder to travel throughout the Schengen area.

The spokesman refused to speculate on possible motives and said the Moroccan authorities and the foreign affairs ministry are investigating.

No-one has yet traveled on the passports, the Moroccan authorities said. They have now been included on European watch lists and registered internationally as stolen.

According to Assabah, 16 people who worked for the courier company have been arrested and questioned about the theft.