(Reuters) -Jailed Kremlin critic Alexei Navalny urged his supporters to show their opposition to the Russian government after a court sentenced him to nine years in prison on Tuesday for fraud and contempt. The 45-year-old was already serving a two-and-a-half year sentence at a prison camp east of Moscow for parole violations related to charges that he says were fabricated to thwart his political ambitions. His existing sentence will be incorporated into the one handed down on Tuesday, said his lawyers, both of whom were briefly detained after the hearing. After sentence was pronounced, Presid…