Chinese police officers wear protective masks at Beijing Station before the annual Spring Festival on January 22, 2020 in Beijing.Kevin Frayer/Getty ImagesChina officially says that supporting Taiwan's independence can be a crime.Punishments include prison sentences of more than 10 years and even the death penalty.It's the first time the country has so clearly outlined a set of legal guidelines aimed at Taiwan.China on Friday outlined a list of behaviors that it defines as criminal acts related to supporting Taiwan's independence, saying punishments may go as far as the death penalty.Top legal bodies in the country — including its Supreme Court, national prosecutors, and three government ministries — jointly issued a statement telling courts and prosecutors at all levels in China to "severely punish 'Taiwan independence' diehards."These are China's first official guidelines designating support for Taiwan's independence as a crime, underscoring how Beijing is hardening its stance toward the self-governed island.Taiwan declaring independence has long been a red line set by Beijing.Broad definitions of the crimes include promoting the idea of "two Chinas" or "one China, one Taiwan" and creating an organization that tries to attain Taiwan's independence.