WASHINGTON  An announcement that the United States would sell more than $6 billion in advanced weapons to Taiwan elicited strong reactions from leaders in China on Saturday, with officials in Beijing issuing denunciations and warnings that the weapons deal could worsen relations.

The Pentagon’s Defense Security Cooperation Agency said in a news release on Friday that it had notified Congress about the proposed arms sales. A State Department spokesman said that Congress had 30 days to raise any objections to the plan.

Among the weapons proposed for sale were $3.1 billion in Patriot Advanced Capability-3 guided missile systems, a sophisticated array of missiles, radars and control systems designed to defend against missiles and aircraft.

Also included in the proposed deal were $2.5 billion worth of Apache attack helicopters and support systems.