We've known for a while that China plans to take back Taiwan. And we know that the US plans to back Taiwan in the event of an invasion. However, China recently announced that if we attack their ships during their invasion, they will NUKE us, and particularly mentioned Los Angeles. Zhu Chenghu, a major general in the PLA states:

If the Americans draw their missiles and position-guided ammunition on to the target zone on China's territory, I think we will have to respond with nuclear weapons."

Update: It turns out that the source webpage has been ALTERED. Now the page reads that this general's statement might not represent the mainstream view of the PLA. Interesting. Interesting that they'd change the article without mentioning the edit.