Taiwan's government on Thursday urged the public to avoid "unnecessary travel" to China after Beijing announced "diehard" supporters of the island's independence could face the death penalty.
China claims democratic Taiwan as part of its territory and has refused to rule out using force to bring the self-ruled island under its control.
Last week, Beijing published judicial guidelines on criminal punishments for supporters of Taiwanese independence, including the death penalty for "particularly serious" cases involving "diehard" independence advocates, state media reported.
Taiwan's top China policy body, the Mainland Affairs Council (MAC), on Thursday raised its travel warning to the second-highest "orange" level as a result.
"After an overall assessment, the government deems it necessary to raise the travel alert on mainland China, Hong Kong and Macau... and advises people to avoid unnecessary travel," said MAC spokesman Liang Wen-chieh.
If Taiwanese people must go to China, Liang advised them to refrain from discussing sensitive issues, photographing military sites, airports and ports, and "carrying books related to politics, history and religion".
Beijing has not conducted top-level communications with Taipei since 2016 and has branded the island's President Lai Ching-te a "dangerous separatist".
On Monday, Lai said China "has no right to punish" Taiwanese people for their views or advocacy.
The United States has also criticized Beijing's death penalty guidelines, with the State Department condemning the "escalatory and destabilizing language and actions of PRC (People's Republic of China) officials."
Beijing has stepped up pressure on Taiwan in recent years and following Lai's inauguration last month China held military drills around the island.