DES MOINES, United States - Chinese President Xi Jinping has said that closer cooperation and exchanges between regions of China and the United States are an important driving force to boost overall bilateral relations.

In a message to mark the 30th anniversary of the sister province/state relationship between China's northern Hebei province and the US Midwest state of Iowa, Xi said cooperation between Hebei and Iowa has made headway in various fields in the past 30 years and that the bond has brought tangible benefits to people in both regions.

The relationship has become an example of region-to-region cooperation between the two countries, said Xi.

China is willing to deepen existing friendly relationships with US states and cities and give full play to governors' forums, city economic cooperation conferences, and mayors' summits to deepen region-to-region cooperation, Xi said in the message dated October 16.

A series of activities were held in Iowa on October 20-22 to mark the 30th anniversary of the sister province/state relationship between Hebei and Iowa.