Outgoing US Ambassador to China Gary Locke has urged Beijing to improve its human rights record and work with Japan to ease tensions in the East China Sea.
In his last speech as ambassador, Mr Locke expressed concern at the recent rise in arrests of journalists and activists engaged in peaceful protest.
He also said that both China and Japan should avoid actions that would be seen as provocative over disputed islands.
Mr Locke, 63, is the first Chinese-American to serve in the position.
He departs on Saturday after gaining a reputation for his modest style and apparent humility.
His term has been marked by a series of delicate diplomatic incidents between the US and China, including a row over blind activist Chen Guangcheng.
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