TEHRAN, Young Journalists Club (YJC) -Taiwan is China's most sensitive issue and is claimed by Beijing as its sacred territory.
Xi has stepped up pressure on the democratic island since Tsai from the pro-independence Democratic Progressive Party became president in 2016.
Tsai rejected Xi's call and instead urged China to embrace democracy.
In Beijing, Chinese Foreign Ministry Spokesperson Lu Kang told journalists that the US' signing into law on Monday (December 31) the Asia Reassurance Initiative Act which reaffirms the US commitment to Taiwan, "interferes with China's internal affairs."
Lu urged Washington not to implement the contents of the law so as not to "damage wider Sino-US relations and the peace and stability of the Taiwan strait."