SAN FRANCISCO (Reuters) - When more than a dozen North Korean economic officials visited California and New York in 2011, U.S. organizers hoped the tour would give the delegation ideas for market reforms and business innovations.  The North Koreans quickly made clear that was not why they had come: They wanted to secure U.S. investment, particularly from restaurant giant Yum! Brands Inc (YUM.N), said Susan Shirk, a University of California at San Diego professor who helped organize the visit.  They really wanted to get KFC to North Korea,  Shirk said, referring to the fried chicken chain. She added that Yum did not reciprocate their interest.  In recent years, a handful of visits from official delegations and athletes have provided rare opportunities for ordinary Americans and North Koreans to come together. Those exchanges are now in jeopardy after President Donald Trump included North Korea in a group of nations that will face travel restrictions to the United States because they do not share enough information about visa applicants. The new policy comes at a time of heightened tensions between the United States and North Korea over Pyongyang s nuclear weapons and ballistic missile tests, as well as escalating verbal threats from the country s leader Kim Jong Un. While the travel restrictions are unlikely to have a broad impact - the number of non-diplomatic travelers from North Korea per year rarely tops 50, according to U.S. State Department data - human rights activists worry it has severed one of the few human bonds between the isolated country and the West.   The main point in inviting these people here is to give them exposure to the U.S., and see if one can open the door a bit,  said Roberta Cohen, co-chair emeritus for the Committee for Human Rights in North Korea. A State Department official said the restrictions were necessary because  North Korea does not cooperate with the United States government in any respect and fails to satisfy all information-sharing requirements  on visa applicants. North Koreans wishing to visit the United States must first obtain permission from their own government, then apply for a visa in person at a U.S. embassy, typically in Beijing, said Robert King, former U.S. special envoy for North Korea human rights issues. When North Koreans arrive in the United States they never go anywhere alone, King said, and are chaperoned by North Korean government minders. In 2015, 15 North Korean weightlifters along with coaches, reserves and officials traveled to Houston for the International Weightlifting Federation world championships, said Phil Andrews, chief executive officer of USA Weightlifting. North Korea was planning earlier this year to take part in the 2017 world championships in Anaheim, California, in November, Andrews said. However, he does not know whether they will be allowed to come.  The new travel restrictions do not affect people who already have visas, and they include waivers for people with certain ties to the United States. The State Department declined to comment on individual visa applications. C. Jerry Nelson, professor emeritus at the University of Missouri, said some visits serve humanitarian purposes. In 2011, four North Korean scientists traveled to Missouri to collaborate with their U.S. counterparts on soil quality testing methods, he said, in order to boost food production. Referring to the economic officials  trip in 2011, Shirk said they seemed reluctant to express opinions but enjoyed their snapshot of American life, which included visits to a mushroom farm, department store and New York s Carnegie Deli.   We arranged for people to go to families for dinner in San Diego,  she said.  They really liked that a lot.  