US President George W. Bush said yesterday he will use diplomacy to try to resolve Iran's nuclear issue but stressed Iran can not be allowed to have a nuclear weapon.

"It's important for our citizens to understand that we've got to deal with this issue diplomatically now," Bush said at a White House press conference.

"And the reason why is because if the Iranians were to have a nuclear weapon, they could blackmail the world. If the Iranians were to have a nuclear weapon they could proliferate," Bush said.

Bush said the United States will continue to work with the EU-3,or France, Germany and Britain, to try to resolve the thorny issue."Our negotiations with Iran on the nuclear weapons will be led by the EU-3," he said.

The United States has insisted on referring Iran's nuclear issue to the United Nations Security Council for possible sanctions. Iran has insisted that its nuclear programs are for civilian purposes only.

In the U.S. National Security Strategy released last week, George claimed that the United States faces "no greater challenge from a single country than from Iran."