The United States will continue supporting the EU-3's efforts to resolve Iran's nuclear crisis through diplomacy, acting spokesman Tom Casey of the State Department Tom Casey said here on Tuesday.

On Iran's nuclear issues, "we've been in constant contact with the IAEA (International Atomic Energy Agency) as well as our friends in the EU-3," Casey said at a news briefing.

Casey also warned to impose sanctions if Iran resumes nuclear program. "Iran absolutely needs to maintain its suspension on all enrichment related activities, including uranium conversion," he said.

"If they were to break that agreement, then the next steps would -- to our way of thinking -- be a referral from the IAEA Board to the Security Council," the spokesman said.

Iran said on Monday it would remove the seal on the uranium conversion facilities in Isfahan after Tehran's deadline for the European Union to submit its proposal on Iran's controversial nuclear program was ignored by the EU.

Source: Xinhua