US warns China against Taiwan attack, stresses US 'ambiguity'

The US national security adviser warned China on Wednesday against any attempt to retake Taiwan by force, saying amphibious landings were notoriously difficult and there was a lot of ambiguity about how the United States would respond.

Robert O'Brien told an event at the University of Nevada in Las Vegas that China was engaged in a massive naval buildup probably not seen since Germany's attempt to compete with Britain's Royal Navy prior to World War I...