Beijing (CNN) China has warned against what it describes as a growing threat from "separatists" in Taiwan, and said it would not rule out using force against the self-governed island Beijing regards as part of its territory.

In a national defense white paper released Wednesday, China took aim at what it considers pro-independence or separatist forces in the far western region of Xinjiang, Tibet and Taiwan, claiming they were a threat to national security and social stability.

In particular, the paper accused Taiwan's democratically-elected government of "pursuing a path of separatism" by pushing for "gradual independence," warning that China "must and will be reunited."

Taiwan has been governed separately from mainland China since the end of the Chinese civil war in 1949, when the defeated Nationalist government fled to the island. Beijing has repeatedly called for "reunification" with Taiwan.

According to the white paper, Taiwan's government under President Tsai Ing-wen is "intensifying hostility and confrontation and borrowing the strength of foreign influence."