KYIV—Three Ukrainian television channels linked to an ally of Russian President Vladimir Putin were blocked from broadcasting on Google’s YouTube on Saturday, the Ukrainian government said, following its request to YouTube to have the channels taken down. The YouTube channels of ZiK, 112 Ukraine and NewsOne did not play their content and instead showed a blank screen with a message saying the channel was not available. “We are pleased such an influential American company is willing to cooperate when it concerns issues of Ukrainian national security and Russian disinformation,” Ukraine’s embassy to Washington said in a tweet. YouTube did not respond to Reuters’ request for comment. The move comes after weeks of tensions between Kyiv and Moscow over the conflict in eastern Ukraine and a Russian troop buildup on Ukraine’s borders that had alarmed Ukraine’s Western backers and the NATO military alliance. Russia said it began withdrawing its troops on …