President Bush has escalated the rhetoric in his standoff with Iran by warning of a “World War Three” unless Iran curb its nuclear ambitions.

President Bush: “So I’ve told people that if you’re interested in avoiding World War III, it seems like you ought to be interested in preventing them from have the knowledge necessary to make a nuclear weapon. And I take this — I take the threat of Iran with a nuclear weapon very seriously. And we’ll continue to work with all nations about the seriousness of this threat.”

Bush’s comments came hours after Iranian officials announced Russia had put forth an undisclosed new proposal to end the nuclear standoff. The Bush administration has insisted Iran halt nuclear enrichment as a precondition to talks. Iran says it’s open to talks but without preconditions. President Bush also defended his veto of a bill expanding health insurance to millions of low-income children. He said using the veto is “one way to ensure that I am relevant.”