Richardson and Google Executive Chairman Eric Schmidt left Pyongyang Thursday following a four-day visit with North Korean officials. Richardson told China's official Xinhua news agency the delegation discussed communication issues with North Korean leaders.
"It is a productive and successful trip," he said. "(We) had a good opportunity with the Korean people and talked about the expanding of Internet, cellphones and more communication."
Xinhua reported that the nine-member delegation met with foreign ministry leaders in Pyongyang and visited computer centers in North Korea.
Richardson, a former U.S. ambassador to the United Nations, told the news agency Monday he was interested in discussing economic and political issues with the North Korean leadership.
Xinhua noted that Richardson is said to have expressed concern about the launch by North Korea of a long-range rocket in December. Launches in 2006 and 2009 coincided with North Korean nuclear tests.
The U.S. government was critical of the visit but said it was a private matter for the delegation. The State Department said none of the members of Richardson's party were carrying an official political message.