Russo-North Korean economic relations have been close since Soviet times. But the collapse of the Soviet Union has negatively influenced the economic relations of both countries. President Putin's 2000, 2001 and 2002 summits with Kim Jong Il were the turning point of the Russo-North Korean rapprochement. Russia was ready to implement plans with North Korea regarding energy, railway, and electricity projects. However, both countries faced an obstacle regarding North Korea's nuclear test and debt to Russia. Removing these obstacles was urgently needed. Moscow has written off 90% of North Korea's debt and will convert the rest into equity in investments as a result of the long, hard negotiations with North Korea. The lifting of these obstacles has reopened the possibility of economic cooperation, for example the trans-Siberian-trans-Korean railway (TSR-TKR) and the trans-Korea gas pipeline. North Korea's new leader, Kim Jong Un, who ascended to power at the end of 2011, announced the reform and opening up of the economy. Moscow has stepped up economic cooperation efforts with Pyongyang, especially since the annexation of Crimea. Nevertheless, there are many obstacles such as North Korea's nuclear program, the deterioration of Sino-North Korean relations, Sino-American tensions and the deterioration of South Korean-Japanese relations.