Police in the Belgian town of Genk have increased vigilance around three mosques after they were desecrated with swastikas and abusive slogans on Thursday night. News of desecration was published by Belgian newspapers on Saturday. A pig head was also left outside one mosque. Mayor of Genk Wim Dries condemned the attacks as "unacceptable." "We won't tolerate this. Nobody wants this kind of signs on a religious building" he was quoted saying. The municipal authorities in Genk are taking the attacks very seriously and the police have already started an investigation to try and find the culprits, said the reports. The town's imams have appealed for calm. The Muslim population in Belgium is estimated to be between 500,000 to 700, 000 in a country of 11 million. There are hundreds of mosques and places of worship for Muslims in Belgium