Ussuri (ōsōˈrē) [key], Mandarin Wusuli, river, c.365 mi (590 km) long, formed by the confluence of the Ulukhe and Daubikhe rivers, S Maritime Territory, Russian Far East. It flows N to the Amur River at Khabarovsk, forming part of the Russia-China border. The Ussuri abounds in fish, and it is used to transport timber. The Ussuri-Khanka lowland is a fertile agricultural region. Armed border clashes between Soviet and Chinese forces occurred (1969 and 1972) along the river, leading to a military buildup. In 1991 in a peace gesture, the USSR announced the transfer of some of the islands in the river to Chinese control. The border was finally settled by Sino-Russian agreements in 2004 and 2008, which involved additional territorial transfers.