Greenspan said via video chat that a number of senior members of the Trump administration look at the imposed tariffs as putting a block on China, but "it's not what's happening."

He said every tariff amounts to a tax, and it is American citizens who will ultimately end up paying.

He pointed out that a trade war will cause a decline in the economic activities throughout the Western world, warning the US to stop before throwing itself into extraordinary difficulties.

He also said that unless the US cuts back on tariffs, all the benefits brought by its previous policies including deregulation and corporate tax reduction will be wiped out.

With the theme, "Exploring New Models of Openness and Regulation", the forum provides a platform for in-depth discussions on topics ranging from globalization and the opening-up of China's financial markets to the new framework of financial regulation.

The two-day event was hosted by Qingdao municipal government and organized by Caijing Magazine and its affiliated Caijing Think Tank.