Russia's media watchdog has written to Google, Twitter and Facebook warning them against violating Russian Internet laws and a spokesman said on Thursday they risk being blocked if they do not comply with the rules. Roskomnadzor said it had sent letters this week to the three US-based Internet firms asking them to comply with Internet laws which critics of President Vladimir Putin have decried as censorship. "In our letters we regularly remind (companies) of the consequences of violating the legislation," said Roskomnadzor spokesman Vadim Ampelonsky. He ...