"Bomb disposal experts searched the building but did not find an explosive device," spokeswoman for Zagreb police Aleksandra Ljuba told Hina.
Croatian Radio Television received a phone call about an explosive device this morning around 9.30 hours.
The spokeswoman did not wish to disclose what exactly did the anonymous caller say, adding that police would give all other information.
A source from Croatian Radio Television who spoke on condition of anonymity said the caller mentioned yesterday's political talk show which focused on inter-religious affairs following Pope Benedict XVI's recent speech in Germany during which the holy father quoted Byzantine Emperor Manuel II Paleologus as saying :"Show me just what Muhammad brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached."
Pope's remarks in the speech have provoked outrage in the Muslim world and led to demands that the pontiff apologise for "insulting" Islam.