Former president Nelson Mandela said on Thursday the United States was preparing to go to war because "George Bush wants to get hold of the Iraqi oil".
He was speaking in Johannesburg at the three-day International Women's Forum, which is being held in Africa for the first time.
Criticism of Bush dominated the former president's address as Mandela encouraged women throughout the world to be "bold with its leadership and condemn the looming war America is preparing for".
"The women's forum must make sure that all irregularities in the world are rectified. A war on Iraq is something we must condemn without reservation," the former president said.
"We must fight globalisation which is for the high and mighty... This is the task of the forum.
"All Bush wants is Iraqi oil, because Iraq produces 64 percent of oil and he wants to get hold of it.
"Bush is acting outside the United Nations and both he and (British Prime Minister) Tony Blair are undermining the United Nations, an organisation which was an idea sponsored by their predecessors."
Mandela also questioned whether the US was ignoring the UN because its secretary-general is black.
"Because they (America) are so arrogant, they killed innocent people in Japan during Hiroshima and Nagasaki," he said referring to the two atom bombs the US dropped on Japanese cities to end the Second World War.
"If (Iraqi President) Saddam Hussein was not carrying out the UN instructions and resolutions... I will support them (the UN) without resignation, but what I condemn is one power with a president who can't think properly... wants to plant the world into holocaust."
The elderly statesman said he was pleased that the people of the world, including Americans, were opposing the US government.
"He (Bush) is making the greatest mistake of his life by trying to cause carnage.
"Why does the United States behave so arrogantly... Their friend Israel has got weapons of mass destruction but because its their ally they won't ask the UN to get rid of it. They just want the (Iraqi) oil... We must expose this as much as possible." - Sapa