(CNN)Dutch police say they have foiled a major terrorist attack by arresting seven men allegedly plotting to target a large event with guns and explosives.
The seven men planned "an attack on a large event in the Netherlands" with the intention of creating a "large number of victims," police said Thursday.
After a monthslong investigation, authorities arrested the suspects, aged 21 to 34 years old, on Thursday, saying they were in the advanced stages of planning the attack.
Two of them were convicted in 2017 for attempting to travel to an ISIS battleground, according to authorities.
One of those convicted is a 34-year-old Iraqi man. Dutch police said in a statement that the suspects "were looking for AK47s, small arms, hand grenades, bombs, bomb vests, and raw material for one or more car bombs."
Police said the attackers intended to use suicide vests and Kalashnikov AK-47s and to detonate a car bomb at another location. Authorities are still investigating the target of the attack.
Earlier this month, an Afghan man was shot by police at Amsterdam's central railway station after stabbing two American tourists.