Emmerson Mnangagwa has been congratulated by Chinese President Xi Jinping on his election as Zimbabwe's president.

Chinese President Xi Jinping has congratulated Emmerson Mnangagwa on his election as Zimbabwe's president, state news agency Xinhua says, offering support after the African nation's opposition cried foul.

Mnangagwa has urged Zimbabweans to unite after he was declared the first elected head of state since Robert Mugabe's removal from power, but the opposition leader has insisted he won and has pledged to challenge the result.

China has close economic and diplomatic ties with Zimbabwe, which it has been keen to maintain after Mugabe's ouster last November in a de facto coup that brought his former ally Mnangagwa to power.

"In a congratulatory message on Sunday, Xi expressed his wishes that the Zimbabwean government and people would make more achievements in national development under Mnangagwa's leadership," Xinhua said.

Xi expects to meet Mnangagwa next month when he visits Beijing for a summit of Chinese and African leaders, it added.

"Xi said he hoped the meeting with Mnangagwa in Beijing could push forward the comprehensive strategic partnership of cooperation between the two countries."

On Monday, Zimbabwe's main opposition said security forces were abducting its members in night raids to intimidate the party and stop it challenging Mnangagwa's win.

Opposition leader Nelson Chamisa has rejected Mnangagwa's victory, and has promised to use legal and constitutional means to challenge the outcome. – SBS News