A prominent Russian opposition figure on Thursday urged Western leaders to stand up to President Vladimir Putin and warned that inaction would make them complicit with "crimes to come." "Time is now for the West to tell Putin that they will not watch quietly anymore," said Garry Kasparov, the former chess champion and Kremlin critic. "The time is now to tell Putin and his gang that there will be economic and political consequences if they continue to turn Russia into a dictatorship because silence is an agreement." Kasparov was speaking to an overflowing audience at the Bruno Kreisky Forum, a respected Austrian center that regularly hosts high-profile speakers. Earlier this month, Kasparov was detained by police as he tried to enter a central square in Moscow where protesters had gathered in defiance of authorities. Police beat dozens with truncheons during the Moscow rally, which was part of a series of so-called Dissenters' Marches that Kasparov helped organize.