People who want to be present at the May 4 Remembrance Day ceremony on Dam square in Amsterdam must have a reservation, organisers Nationaal Comité 4 en 5 Mei have said.

The measure is a result of a decision by Amsterdam mayor Femke Halsema to tighten up security at the event, during which the Netherlands remembers the Dutch who died in World War II and subsequent wars.

The measures include allowing fewer people into the area around the Dam due to “heightened tensions in society and greater readiness by campaigners to take action,” Halsema said last week.

Some 10,000 people instead of the usual 20,000 will now be allowed to attend. The reservation is also meant to make room for “vulnerable people” who come from outside the city and who may have trouble finding a spot.

As part of the more stringent safety measures every visitor will be searched upon arrival and all flags and other political symbols will be confiscated. According to the Parool, t shirts with the slogan “free Palestine” will also be banned, even though, according to experts, there is no legal basis to do so.

The main ceremony, attended by the king and queen, takes place on the Dam but there are hundreds of others all over the country.