PODGORICA (Reuters) - Montenegro police used teargas to disperse hundreds of people protesting against the enthronement of a Serbian Orthodox Church cleric as the nation's religious leader on Sunday, a ceremony that has exposed deep divisions over ties with Serbia.

       The demonstrators in the town of Cetinje had thrown rocks, bottles and fire crackers at police as church figures were flown into the town by helicopter, news site Vijesti reported, but there were no reports on injuries on either side.

       The enthronement of Joanikije II as the church's top cleric in the country, known as the Metropolitan of Montenegro and Archbishop of Cetinje, was being held under heavy security in a monastery in the town.

       The protests reflect tensions in the Balkan country between those who advocate closer ties with Belgrade and others opposing any pro-Serb alliance.

       Montenegro left its union with Serbia in 2006 but its church did not become autonomous and remained under the Serbian Orthodox Church - in the eyes of some, making it a symbol of Serbian influence.

       Prime Minister Zdravko Krivokapic described attacks on police in Cetinje as "an act of terrorism".

       He blamed President Milo Djukanovic's Democratic Party of Socialists of the President Milo Djukanovic, which ruled the country for three decades before losing elections last year, for organising the protests.

       Djukanovic opposes the enthronement, but has not commented on Krivokapic's allegations of organising the demonstrations. Djukanovic's adviser Veselin Veljovic was arrested for participating in an attack against police on Sunday, state TV reported.

       The EU special envoy for Montenegro, Tonino Picula, said that the rising tensions were worrying.

       "The freedom to expression, but also to protest is inviolable," Picula told state TV.

       (Reporting by Stevo Vasiljevic and Ivana Sekularac; Editing by Pravin Char)