MOSCOW—A Russian organization that tracks political arrests and provides legal aid to detainees said Saturday that government regulators blocked its website, the latest move in a months-long clampdown on independent media and human rights organizations. OVD-Info reported that Russia’s internet and communications watchdog, Roskomnadzor, blocked the group’s website. The organization said in a tweet that it wasn’t formally notified about the decision and doesn’t know the reason for the action beyond that it was ordered by a court outside Moscow on Monday. The website was unavailable to Russian internet users on Saturday and was listed on the government’s registry of banned web pages. In light of the move, OVD-Info urged supporters to follow its pages on a number of social media platforms, such as Facebook, Twitter, Instagram, Russian social network VK, and messaging app Telegram. In comments to the Interfax news agency, Roskomnadzor said the website was blocked because, according …