An announcement that the United States will sell more than 6 billion USD in advanced weapons to Taiwan elicited strong reactions from leaders in China , with officials in Beijing issuing denunciations and warnings that the weapons deal could worsen relations. U.S. foreign policy recognizes only one China , with its capital in Beijing , but stresses that reunification with Taiwan , which split from the mainland in 1949, must be achieved through negotiations. Washington has pledged to support Taiwan in any unprovoked attack from China .