evidence: Border disputes have been a major source of animosity between China and Russia. The two nations have disputed ownership of Bolshoi Ussuriysky (known as Heixiazi, or Black Bear, in Chinese) for years, with both nations coming to an agreement in 2004 on the matter after almost four decades of talks. [...] "Russia has suggested cross-border checkpoints. These would allow eight-seater or smaller cars to travel between Khabarovsk, one of the largest cities in Russia's Far East, and Fuyuan in Heilongjiang province, the most easterly town in China," Zhou Hong, director of the Heixiazi Island Development and Management Committee, said at the time.