MOSCOW (Reuters) - Russian prosecutors suspended a leftist opposition group for three months on Friday in what critics of President Vladimir Putin say is an intensifying crackdown on dissent sponsored by the Kremlin.

Since the start of his third term last May, Putin has signed laws increasing fines for protesters and tightening controls of foreign-funded groups while several opposition activists face prison terms in cases they say are trumped up.

The decision by Moscow prosecutors on Friday means the Left Front, whose leader Sergei Udaltsov played a prominent role in street protests last year against Putin, is not allowed to hold meetings or protests, or use its symbols or bank accounts until July 19.

That would cover the first anniversary of Putin's presidential inauguration when the opposition groups have vowed to stage a mass demonstration to revive the protest movement that has died out over the winter.

"We consider the Moscow prosecutor's office actions a political order aimed at closing down the Left Front," said Udaltsov's twitter account, which has been run by his aides since the shaven-headed activist was placed under house arrest.

The prosecutor's office said the Left Front failed to declare its goals, as required, and did not publish annual financial reports. It said the group had not responded to earlier calls to respect the law.

"They have three months now to change that or the next step is to seek a closure of the group altogether," prosecutor's office spokeswoman Yelena Rossokhina said.

The Left Front said it would appeal against the decision and in the meantime operate as the New Left Front.

The Kremlin denies cracking down on critics amid growing Western criticism that Moscow is rowing back on democratic freedoms.

(Reporting by Gabriela Baczynska; Editing by Michael Roddy)