The sole reason for a possible US-led attack on Iraq would be to gain control of its oil resources, Mr Nelson Mandela said yesterday, adding that President Bush "can't think properly".
The former South African president also attacked British Prime Minister Mr Tony Blair, describing him as the "US foreign minister", in a criticism of London's close alliance with Washington over Iraq.
"He is no longer Prime Minister of Britain," Mr Mandela declared at the opening of the three-day International Women's Forum in Johannesburg.
"Bush is acting outside the United Nations and both he and Tony Blair are undermining the United Nations, an organisation which was an idea sponsored by their predecessors. Why does the United States behave so arrogantly?
"Their friend Israel has got weapons of mass destruction, but because it's their ally, they won't ask the United Nations to get rid of them.
"They just want the oil ... We must expose this as much as possible," Mr Mandela said. "All Bush wants is Iraqi oil.
"He is making the greatest mistake of his life by trying to cause carnage."
Mr Mandela has consistently criticised US policies in the past year, voicing his staunch opposition against a war on Iraq, in line with more diplomatic statements issued by Pretoria.