Prague - A man who went to a mosque Thursday morning in Prague-Kyje district for a morning prayer soon found himself in a state of shock.

He discovered a pig head fixed to a fence of the mosque with an inscription "NO TO ISLAM". The man called the police which have launched investigation of the incident.

"It is not clear yet whether it is an offence or a crime," Prague police spokesperson Jan Mikulovský told press agency ČTK.

The police are viewing the CCTV footage, while investigating witnesses.

Photographs of the pig head appeared on the web site of the far right National Party. The party is known for its anti-Islamic stands, calling for banning Islam in Europe. The web site says:

"How will those who decapitate Christians or kill and rape non-believers... feel when they see an unclean pig among their rank?"

Muslims regard pigs as unclean animals. Presenting a pig to them constitutes an offence.