Biden tells China not to count out U.S. strength

"We are still the single best bet in the world, in terms of where to invest," Biden told a university audience in Chengdu, the provincial capital of Sichuan, the southwest province that is the second and last stop of his visit to China.

"Please understand that no one cares more about this than we do, since Americans own 87 percent of all our financial assets and 69 percent of all our treasury bonds," Biden said, answering a question about U.S. debt.

"So our interest is not just to protect Chinese investment. We have an overarching interest in protecting the investment, while the United States has never defaulted and never will default."

"You're safe," he added.

Biden also used his speech to renew U.S. calls for Beijing to do more to rein in North Korea and Iran, whose nuclear ambitions have alarmed the West.

"The fact is, China and the United States face many of the same threats and share many of the same objectives and responsibilities," he said.

But his key theme was, as it has been throughout his five-day visit to China, economic: that the United States can reverse its high debt and low growth, and that China should play a part by buying more American-made goods and services.