China's President Hu Jintao called the international currency system, which is dominated by the U.S. dollar, a product of the past but said it would be a fairly long process to make China's own currency an international one.

Hu, who will visit Washington this week, also said the liquidity of the U.S. dollar should be kept at a reasonable and stable level. He made the comments in a very rare written interview with two U.S. newspapers, the Wall Street Journal and the Washington Post.