Cosatu has called on the government to impose sanctions against Israel.
The call comes amid attacks by Israeli armed forces on Gaza, the Palestinian territory governed by Hamas.
Cosatu general secretary Zwelinzima Vavi said South Africa should cut diplomatic ties with Israel and institute sanctions until it ends its 40 years of military occupation of Palestine.
Archbishop Desmond Tutu was quick to condemn the Israeli attack, saying it "bore all the hallmarks of war crimes".
ANC spokesman Jessie Duarte said: "We condemn Israel's outrageous and unacceptable air strikes against the Palestinians."
South African Council of Churches general secretary Eddie Makue said "drastic action needs to be taken against Israel because to go into Gaza and shoot children with sophisticated military hardware is atrocious".
Meanwhile, about 300 people protested in Cape Town yesterday, calling for sanctions against Israel.
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