Saint Petersburg - Russia's powerful Orthodox Church faced off on Sunday with thousands of protestors in this northwestern city over the fate of a cathedral that is one of the city's top tourist attractions.The city is preparing to hand over control of the central St Isaac's Cathedral - Russia's largest - to the Orthodox Church after decades as a museum.But the decision has sparked a furious row, pitting clerics against locals who feel aggrieved the city is handing over a key tourist asset to the Church without public consultation.The imposing domed cathedral built in the 19th century is popular with tourists who climb up onto its roof for a spectacular view.Rights of believersWhile some religious services are held there, the cathedral is run as a museum with an entry charge. After Russia's 1917 revolution, the atheist Bolsheviks took over churches, stripping them of valuables and using them as factories or storerooms. St Isaac's Cathedral served for a time as a Museum of Atheism. In the latest round of protest action, about 400 clerics and believers on Sunday held a procession around the cathedral carrying crosses.Among those taking part was MP Vitaly Milonov, who spearheaded controversial anti-gay legislation.He said that keeping the cathedral as a museum is "an infringement of the rights of believers".The cathedral has become "a kind of circus for tourists," he said.The protest's organiser, lawmaker Boris Vishnevsky of the Yabloko liberal party, said "the fact that there are so many of us will force the authorities to back down."A previous demonstration by opponents of the handover on January 28 saw some 1 500 gather in a city park.Paperwork drawn upThe "no" campaign has been backed by key cultural figures, notably the director of the nearby State Hermitage Museum, Mikhail Piotrovsky, who wrote to Russian Orthodox Patriarch Kirill asking him to delay the handover to cool tensions.So far there has been no official reaction to the protests. The handover was announced in January and the paperwork is being drawn up. Meanwhile the opposition has launched legal action, that so far has been unsuccessful, and organised demonstrations.