The chief suspect in the raids in three cities was Samir Azzouz, a 19-year-old Dutch national of Moroccan descent, who was acquitted of terrorism charges earlier this year, prosecutors said.
Mr Azzouz was allegedly in the process of purchasing automatic weapons and explosives, "probably to carry out an attack with others on several politicians and a government building", a prosecution statement said. The suspects, who range in age from 18 to 30, were detained in The Hague, Amsterdam and Almere. They will be brought before a judge on Monday.
Officers in riot gear closed entrances leading to both houses of parliament and the government's information service. The National Terrorism Combat Coordinator boosted security at the justice and home affairs ministries, the secret service and other government buildings as a precaution, a statement said, but it saw "no reason to increase the national terrorism threat level".
Police declined to give details about the raids, but there were reports of gunfire in the streets. The arrests came just days after renewed threats were made against the MPs Ayaan Hirsi Ali and Geert Wilders, both critics of Islamic extremism. Mr Wilders filed charges earlier this week after receiving a threat. The two went into hiding for months after the murder of the film-maker Theo van Gogh last November.Reuse content