China strongly condemned Wednesday an Israeli air strike in Lebanon that killed a Chinese United Nations observer and summoned Israel's ambassador in Beijing to demand an apology.

In its first reaction to the death of the Chinese national and up to three other UN workers in Tuesday's strike on the hilltop town of Khiam, China also called for an immediate ceasefire in the conflict by all sides.

"The Chinese side is deeply shocked and strongly condemns this," foreign ministry spokesman Liu Jianchao said in a statement, adding the strike had killed "many innocent victims".

"The Chinese side demands that all sides in the confrontation, especially Israel, take all measures to ensure the safety of UN peacekeepers."

Liu said Chinese assistant foreign minister Zhai Jun had called in Israeli ambassador Yehoyada Haim on Wednesday morning for an "emergency" meeting over Tuesday's incident.

"The Chinese side… demands that the Israeli side open a comprehensive investigation, apologize to the Chinese side and the victim's family and help the Chinese side in carrying out the mourning activities," Haim was told, according to Liu.

China said an immediate end to hostilities was necessary.

"We urge all parties to immediately implement a ceasefire and quickly return to the path of negotiation," Liu said.

"China will make more diplomatic efforts with the international community to push forward the resumption of peace and stability in the Middle East region."