The Hague - Four of the largest mosques in The Netherlands said on Monday they will shut their doors during major prayer meetings after six people were killed in attack on a Canadian mosque.The Blue Mosque in Amsterdam, The Hague's as-Sunnah Mosque, Rotterdam's Essalam Mosque and the Omar Al Farouq Mosque in Utrecht said in a statement "we feel compelled to close mosque doors during prayers."Additional safety cameras have also been set up at the Blue Mosque, situated in the southwestern suburbs of the Dutch capital.Several thousand people attend prayers at the four mosques daily."Merciless acts such as in Quebec contribute to the growing global hatred of Muslims," Said Bouharrou of the Dutch Moroccan Council of Mosques (RMMN) told AFP."A mosque is an open building that should be accessible at any time of day to all people looking for peace and calm.""But we have to be alert against these terror attacks. It's disappointing that these stringent safety measures should be put in place," Bouharrou said, adding mosque leaders were in close contact with the Dutch National Co-ordinator for Security and Counterterrorism (NCTV).Six people died and eight others were injured late Sunday when gunmen opened fire at a Quebec City mosque in a shooting Canadian Prime Minister Justin Trudeau called a "terrorist attack".The Netherlands is facing parliamentary elections in March with anti-Islam politician Geert Wilders leading in opinion polls.Wilders said he would close all mosques and Islamic schools and ban the Qur’an if he becomes the country's next prime minister.Although no specific threats have been made against mosques in The Netherlands, Bouharrou said the RMMN was keeping a close eye on political developments, ahead of next month's vote."There is considerable anxiety ahead of these elections. A politician like Mr Wilders has had clear viewpoints (about Islam) over the last few years," he said.