An Islamic school in the Dutch city of Eindhoven was hit by an explosion but no one was injured, ANP news agency reported. Windows at nearby buildings were blown out. Eindhoven mayor Alexander Sakkers told public Dutch radio that no one was hurt in the explosion but that people in the neighborhood were in shock. Muslim houses of worship and Islamic schools have been under surveillance since the murder Tuesday of van Gogh but police patrols would be stepped up, he added. ANP reported Sunday that three Dutch mosques had been targeted in failed arson attempts at the weekend. Police arrested three suspects as they tried to set fire to the An-Nasr mosque in the western town of Huizen Friday night. Unidentified suspects also attempted to set fire to a mosque in Breda in the south, although the fire had petered out by the time police reached the scene. In Rotterdam, a palette was set alight at the Mevlana mosque, but the fire did not spread. Pig heads and a placard with insulting slogans were nailed to the door of another mosque in the port city. Vandals also daubed red paint over a Moroccan associative building in Amsterdam at the weekend. Tensions are running high in the Netherlands in the wake of the brutal killing of film-maker and columnist van Gogh. A suspected killer of Moroccan origin is being held over the killing. Van Gogh was widely known for his criticism of Islam and recently caused an uproar with a short film linking domestic abuse with the perceived subservient position of women in the Islam. The Netherlands is home to almost a million Muslims or about 6% of its population of 16 million. The majority of Muslims are from Turkey and Morocco. A poll by RTL Nieuws showed 47% of respondents said they felt less tolerant of Muslims after the killing of van Gogh, while another survey showed support for a populist who wants to stop immigration from Turkey and Morocco rising to 12%. **PHOTO CAPTION*** Dutch Mosque.