Anti-Putin campaigner to be tried on 17 April as tensions mount across Moscow in the wake of last year's protestsA provincial Russian court has announced it will launch the trial of Alexey Navalny on 17 April, in a case widely believed to be targeted at silencing the popular opposition leader.The case against Navalny, one of the loudest critics of Vladimir Putin, threatens to revive the tensions that swept Moscow last year, when thousands of people took to the streets of the capital to protest against the powerful president's longtime reign.