Dutch police arrested four men suspected of involvement in a terror plot meant to strike New Year’s Eve celebrations after receiving a tip-off earlier in the week.

One of the arrested men was a Syrian national and another Egyptian, reports NOS, with all arrests taking place in the Dutch city of Rotterdam on Saturday. The news service reported that all of the arrested men were of “non-Western” backgrounds and were in their 20s.

A fifth man, also Syrian, was arrested in Mainz, west Germany on Saturday, which is reported to be a terror arrest related to the Netherlands four and at the request of the Dutch government.

No weapons or extremist material is understood to have been recovered in the course of the raids, which were led by special police teams, and which were triggered by a tip-off about a plot to launch an attack.

A police spokesman said of the arrests: “They are suspected of involvement in the preparation of a terrorist crime… Investigations will continue in the coming days, with the emphasis on further investigation of the nature and scale of the terrorist threat”, reports The Times.

These latest actions by the Dutch security services follow others in 2018, with seven arrested in Arnheim in September on suspicion of planning a “large-scale” terror attack. The ringleader of the alleged cell was reported to be an Iraqi male who had planned a mass casualty attack involving firearms and explosive vests at a large public event.

Police said in a statement the suspects were in the process of attempting to acquire AK47 assault rifles, handguns, bomb vests, grenades and raw materials for bombs and were looking for opportunities to train with such weapons.

The Dutch anti-terror coordinator’s office said after the arrests that: “Jihad networks are also active in the Netherlands with the intention to plot attacks in Europe… Today’s arrests must be seen in that light.”