The US Secretary of State Colin Powell will give details on Wednesday of new evidence that Iraq is not getting rid of its weapons.
UN inspectors are searching for weapons in Iraq
They are supposed to be obeying an important United Nations rule that says they must destroy weapons, but the US don't think they are.
They want to use military action to force the country to disarm, but lots of people around the world don't think there is enough evidence to support starting a war.
At the moment UN weapons inspectors are searching Iraq for weapons of mass destruction, but the inspectors don't think Iraq is doing enough to help that search.
Fact File
Key dates
5 Feb - US Secretary of State Powell to address UN Security Council
14 Feb - further report from weapons inspectors
27 Mar - Chief weapons inspector Hans Blix submits new report to UN
So Secretary Powell is going show the UN some of the evidence that his government has got to prove Iraq has weapons.
Powell is expected to use satellite images showing ways Iraq is blocking the inspectors, and audio proving Iraqi officials are deceiving UN weapons inspectors.
The US hope that the new evidence will be enough to convince the UN that military action is necessary, although if the UN still doesn't agree, America may start without them.
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