JOHANNESBURG, Jan 30: The sole reason for a possible US-led invasion on Iraq would be to gain control of its oil resources, Mr Nelson Mandela said on Thursday, adding that President George Bush "can't think properly".

The former South African president also attacked British Prime Minister Tony Blair, whom he said had been newly deployed as the "US foreign minister" in a criticism of London's close alliance with Washington over Iraq.

"He (Blair) is no longer prime minister of Britain," Mandela opined at the opening of a 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."

Mandela said the "arrogant behaviour" by the United States was mainly motivated by Iraq's rich oil reserves.

"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," Mandela said.