An email newsletter from Eurasia Group contains the following paragraph, and I’ve bolded the statement relevant to the question:
In recent months, the temperature has risen as the US broadens its diplomatic support for the pro-independence leadership that won Taiwan’s elections in 2016, while China has increased its efforts to diplomatically isolate and militarily threaten the island. Chinese officials have warned that if the US keeps up its new overtures to Taiwan, Beijing could move to forcefully reunite the island with the mainland – a longstanding threat that carries new weight under the assertive leadership of President Xi Jinping.