North Korea says it will set up an economic zone on two islands on the border with China. The North Korean official news agency KCNA made the announcement on Monday, a few days after the country's leader Kim Jong Il returned from a trip to China to study its economic development. The news agency says the North Korean Supreme People's Assembly had issued a decree setting up the Hwanggumphyong and Wihwa Islands Economic Zone in order to boost friendship with China and expand and develop external economic relations. It says the zone will be under North Korean sovereignty.Mr. Kim visited China last month, his third trip there in just over a year. China is North Korea's closest ally and its largest aid donor. Chinese Premier Wen Jiabao said Mr. Kim was invited to learn from China's economic development.