* State media, officials start anti-tower campaign
* Gazprom says not backing off for now
By Denis Pinchuk and Dmitry Zhdannikov
MOSCOW, Nov 16 (Reuters) - Prime Minister Vladimir Putin, an early supporter of a controversial project to build St Petersburg's first glass skyscraper, is now expected to scrap it because of mounting opposition at home and abroad.
The 403-metre (1,322-foot) tower, intended to house offices of state-run gas giant Gazprom (GAZP.MM) by 2016, has caused an outcry among inhabitants of St Petersburg, Russian opposition parties and the U.N. cultural agency UNESCO [ID:nLN573166].
Putin has said he supports the $3 billion project in his home town as it would help the economy of the former imperial capital and revive a neglected corner of the city -- but that a decision lies with the city authorities.
Opponents say the tower would ruin the unique skyline of the city, often dubbed Russia's Venice. State media and some officials have begun to express doubts after years of support.
UNESCO has warned Russia it could exclude St Petersburg from its list of world heritage sites if the tower is built, as it would dominate the canals and baroque houses of the city founded by Tsar Peter the Great in 1703 as Russia's window on Europe.
"It is very likely that it will be Putin who will draw a line under the project," said Maxim Reznik, leader of opposition party Yabloko in St Petersburg, who is suing the city administration in court in an effort to get the project dropped.
Putin's approval ratings fell in November for the first time since the start of the economic crisis [ID:nL2370140] and aides reacted with a campaign to improve his image [ID:nLD654404].
"Putin has always been against imposing his opinion on citizens and those in the city who take architectural decisions," said Putin's spokesman Dmitry Peskov.
He declined to say whether Putin could scrap a project already approved by the office of St Petersburg's mayor.
Three years ago Putin ordered a key oil pipeline to be rerouted after protests by ecologists who said it could endanger Lake Baikal, the world's deepest lake, and its rare species.
Putin stepped down as president last year but remains Russia's most powerful politician, and most Russians believe he will run for president again in 2012."
Some officials have expressed concern about the project.
"Russia's Regions Ministry believes that it is not reasonable to place a 400-metre building in direct proximity to world heritage cultural sites," the ministry said last week.
Culture Minister Alexander Avdeyev said in October he was sceptical about the tower.
Gazprom spokesman Sergei Kupriyanov said chief executive Alexei Miller, a close Putin ally, was aware the debate was heating up. "We are continuing all work and there has been no order to back off," he said.
Maxim Shevchenko, a popular presenter on the main state TV channel ORT, conducted a fierce anti-Gazprom debate on ORT last week, contrasting sharply with the usual image of Gazprom as Russia's most important firm.
"By showing such stubbornness, Miller has managed to turn a simple construction and architectural issue into almost a political issue," Shevchenko told Reuters. "If Miller takes the issue so personally, I guess there is only one authority for him -- Putin." (Writing by Dmitry Zhdannikov, editing by Tim Pearce)