China's leadership has long been wary of anyone capable of amassing a social following, especially after thousands of pro-democracy protesters in Tiananmen Square boldly challenged one-party rule in 1989. With social media now able to rapidly spread information, religious and human-rights groups say Chinese leaders are further tightening controls by targeting people who show just the potential of emerging as social actors. The moves reflect a harder line under President Xi Jinping, who also has taken a tougher stance against China's neighbors and rivals in his own party since rising to power last year, said Chan Ka Wai, the Hong Kong-based executive director of the China Human Rights Lawyers Concern Group. A document believed to outline the Chinese leadership's top perceived threats to its power cited civil society, warning that "Western anti-China forces" have "launched all kinds of so-called citizen's movements." Advocates of civil society want to squeeze the party out of leadership of the masses at the local level," it read, adding that "their advocacy is becoming a serious form of political opposition. The Flight 370 relatives appeared to have crossed a red line when they began loudly demanding more support from Chinese leaders in their quest for more information on the flight, which disappeared March 8 over the Indian Ocean with 239 people aboard, most of them Chinese. A Harvard University study released last month found that Chinese censors have most consistently targeted posts dealing with protests, government scandals and other topics with the potential for collective action, even if they're urging pro-government action. Religious scholars say government leaders have watched with alarm as Christianity has flourished in the province, and as the Christian population nationwide approaches China's 85 million Communist Party members.