US Secretary of State Condoleezza Rice has warned Iran that it must face the consequences of its defiance over its nuclear programme.
Ms Rice said the United Nations must consider strong action against Iran, such as a resolution that could lead to sanctions or lay the groundwork for force.
Asked what options the UN Security Council should consider, Ms Rice said it should look at chapter 7 of the UN Charter to force Iran to comply with international obligations over its nuclear plans.
"I am certain we will look at measures that can be taken to ensure that Iran knows that they really have no choice but to comply," Ms Rice told reporters.
Chapter 7 makes a resolution mandatory under international law for all UN members.
It can lead to sanctions and eventually the use of force if it specifically calls for them or threatens "all necessary measures."
A Chapter 7 resolution passed against Iraq has been seen as giving the United States a legal argument for the bombing and then invasion of that country. Russia, in particular, fears that the United States might interpret a Chapter 7 resolution in the same way against Iran.
Russia and China, key players on the Iran issue with veto rights in the Security Council, strongly oppose sanctions or the use of military force against Tehran.
All other council members, including close ally Britain, oppose military action.
The United States, believing Iran is intent on making an atomic bomb, has said that while all options are on the table, it is pursuing the diplomatic course and rejects reports that it is stepping up plans for a military strike.
Ms Rice, who has called for "strong steps" against Iran, said Tehran had done nothing to show it planned to adhere to calls by the international community to abandon its nuclear plans and the world must respond.
"We are going to have to have a response and it can't be another presidential statement," said Rice, referring to a statement issued by the Security Council last month against Iran.
The Security Council has told Iran to halt all sensitive atomic activities and on March 29th it asked the IAEA, the UN nuclear watchdog, to report on its compliance in 30 days.
Iran's declaration this week that it enriched its first batch of uranium is unlikely to spur the divided Security Council to take any substantive action sooner than May on the question, council diplomats said on Wednesday.