US President Bush has left open the option of a military attack on Iraq to oust Saddam Hussein, saying the Iraqi president "needs to understand I am serious."
A senior US official says Mr Bush's top advisers and agencies of the government has been directed to develop and refine a "full range" of options.
The official says the recommendations will then be circulated within the government and sent to the White House so Mr Bush can make a final decision.
After meeting Pakistani President Mr Pervez Musharraf at the White House, Mr Bush acknowledged that he is considering various options to deal with Saddam, but he would not disclose any details.
"I will keep them close to my vest," Mr Bush said. "President Saddam Hussein needs to understand I am serious about defending our country."
But Mr Bush also says any alliance between terrorist organisations and terror-supporting nations with a history of pursuing nuclear or other destructive weapons will be "devastating for those of us who fight for freedom," and the United States will not tolerate it.
"We, the free world, must make it clear to these nations they have a choice to make," Mr Bush said. "I will keep all options available if they don't make the choice."
CIA Director Mr George Tenet is said to favour a plan that relies heavily on covert action, rather than an open military campaign. The Central Intelligence Agency is already authorised to try to destabilise the Baghdad government.
Secretary of State Mr Colin Powell suggested, apparently in jest, that "natural causes" might be the solution. Mr Powell, 64, noted Saddam was the same age but said he does not appear to be in as good condition.
Mr Powell and other senior administration officials says the preference is to bring down Saddam with political and diplomatic measures.
PA