Hinggan, Tongliao, and Chifeng, and sometimes Xilin Gol Areas of the modern Russian Federation also known as "Outer Northeast China" or "Outer Manchuria". The two areas involved are Priamurye between the Amur River and the Stanovoy Range to the north, and Primorye which runs down the coast from the Amur mouth to the Korean border, including the island of Sakhalin First used in the 19th century by the Japanese, the term is deprecated among people of the People's Republic of China (PRC) due to its association with pro Japanese imperialism, the historical puppet state of Manchukuo of the Empire of Japan, and its origination of alleged contemporary "Manchurian nationalism". Official state documents use the term Northeast Region (东北; Dōngběi) to describe the region. Northeast China is predominantly occupied by Han Chinese due to internal Chinese migrations and Sinicization of the Manchus especially during the Qing dynasty. It is considered the homeland of several minority groups besides the Manchus, including the Yemaek the Xianbei, the Shiwei, and the Khitans. The area is also home to many Mongols and Hui. Manchuria is often referred to as the "Chinese rust belt", due to the shrinking cities that used to be the center of China's heavy industry and natural resource mining, but today face increasing economic decline. Boundaries Manchuria is now most often associated with the three Chinese provinces of Heilongjiang, Jilin, and Liaoning. The former Japanese puppet state of Manchukuo further included the prefectures of Chengde (now in Hebei), and Hulunbuir, Hinggan, Tongliao, and Chifeng (now in Inner Mongolia). The region of the Qing dynasty referenced as Manchuria originally further included Primorskiy Kray, the Jewish Autonomous Oblast, the southern parts of Amur Oblast and Khabarovskiy Kray, and a corner of Zabaykalʼskiy Kray. These districts were acknowledged as Qing territory by the 1689 Treaty of Nerchinsk but ceded to the Russian Empire due to the Amur Annexation in the unequal 1858 Treaty of Aigun and 1860 Convention of Beijing. (The People's Republic of China indirectly questioned the legitimacy of these treaties in the 1960s but has more recently signed agreements such as the 2001 Sino-Russian Treaty of Friendship, which affirm the current status quo; a minor exchange nonetheless occurred in 2004 at the confluence of the Amur and Ussuri rivers.) Various senses of Greater Manchuria sometimes further include Sakhalin Island, which despite its lack of mention in treaties was shown as Qing territory on