Police placed a protective cordon around the main complex of government offices and parliament and stormed into several homes, detaining at least seven supsects in an operation meant to disrupt an alleged plot to attack politicians and public buildings. Among those reportedly arrested during the sweep in three cities was a young Dutch-Moroccan who had been acquitted of terrorist-related charges earlier this year. The raids, staged just weeks before the first anniversary of the Islamist killing of a Dutch filmmaker, underscored what officials believe to be an ongoing threat by cells of extremists targeting prominent Dutch personalities. Officials said the suspects, aged from 18 to 30 years, were detained in The Hague, Amsterdam and Almere. They will be brought before an investigating judge Monday.