MOSCOW (Reuters) - The U.N. cultural agency called on the Russian government on Wednesday to halt plans to build a steel skyscraper among the baroque mansions of St Petersburg's historic center.
The 403-meter (1,322-foot) tower, intended to house the headquarters of the state-controlled Russian gas firm Gazprom, has caused an outcry among opposition groups.
"We're hoping the (federal) decision to build it won't be taken. It will damage the image of Russia," Grigory Ordzhonikidze, the head of UNESCO in Russia, told Reuters.
Authorities in the former imperial capital on Tuesday approved the construction of the tower, which developers say will cost at least $3 billion.
If built, it would be as tall as the Eiffel Tower in Paris and would dominate the canals and pastel-colored houses of the city, founded by Czar Peter the Great in 1703 on the Baltic as Russia's window on Europe.
It could mean Russia's second city being added to UNESCO's list of endangered world heritage sites, Ordzhonikidze added.
Both President Dmitry Medvedev and Prime Minister Vladimir Putin call St Petersburg their home town.
"They understand that they can do anything as there is no punishment waiting for them," Boris Vishnevsky, a member of the liberal Yabloko party, told Reuters.
"It seems Putin has become an outsider to St Petersburg."
Vishnevsky said the tower would far exceed the standard height of buildings in city.
The project's backers say it will bring investment to a neglected corner of the city and the design will complement the surrounding architecture, a notion dismissed by conservationists.
"St Petersburg is unique not because of one building or one historical monument but due to the entire architectural ensemble," said Antonina Yeliseyeva from the preservationist Zhivoi Gorod (Living City) group.
"We simply cannot let this eyesore to be built in the center."
Additional reporting by Aydar Buribayev and Guy Faulconbridge; editing by Andrew Dobbie