China has tried to get a foothold in Rajin for several years, after North Korea designated it a free-trade zone. Rajin has five ports; until now Russian companies had secured rights to one and Chinese companies to another.

“With the lease, China can develop the port and build infrastructure there as it desires," Liu Ming, director of Korean Peninsula studies at the Shanghai Academy of Social Science, told the South China Morning Post. He added that Chinese authorities plan to use the port not only for shipping goods and raw materials but also for tourism, because it facilitates travel to Russia, Japan and South Korea.

The city could also become an important trade hub for North Asia. At present, most of the goods exported to South Korea and Japan from the northeast of China have to be shipped through the port city of Dalian in Liaoning. Liu Ming said that using the Rajin port would result in significant savings in terms of costs and time.

China’s State Council (cabinet) plans to turn Jilin's Tumen River area into an economic development zone that would cover the provincial capital of Changchun, the city of Jilin and Yanbian.

The mainland lost port access to the Sea of Japan in the 19th century to Japan. Since then, resource-rich regions like Jilin and Heilongjiang have been without a direct maritime outlet.

Liu Jiangyong, a professor of international relations at Tsinghua University's Institute of International Studies, noted that leasing of the Rajin port would enhance regional economic integration. “This is also a sign that North Korea is planning to further open up, at least for economic co-operation,” he said.