The top U.S. diplomat for East Asian affairs expressed concern Saturday over the persistent wrangling between Japan and China and said he hopes Asia's two biggest economies will settle the Senkaku dispute and other disagreements in a peaceful manner.

"The friction and tension between Tokyo and Beijing is a matter of concern to all neighbors and certainly to the United States," Daniel Russel, assistant secretary of state for East Asian and Pacific affairs, told reporters in Beijing, the last leg of his five-country Asian tour.

"We hope leaders on all sides will exercise restraint and sensitivity, and will consistently pursue diplomatic and friendly means to manage disputes or to resolve outstanding issues," Russel said after meeting with senior Chinese officials, including Foreign Minister Wang Yi and Liu Zhenmin, vice foreign minister in charge of Asian affairs.