The head of the International Atomic Energy Agency says a resolution on Iran's nuclear activities adopted by the agency Wednesday is good for peace, but warned that Tehran must now fully cooperate with the international community.

The head of the IAEA, Mohamed ElBaradei, told a press conference that the resolution on Iran's nuclear activities sends what he called a serious and ominous message to Tehran.

"I think a number of board members today during the discussion made it clear that this means that the board will look into the option of reporting to the Security Council. However, the language is clear that the board will make use of all options available to it if any failures were to come to light in the future."

The resolution adopted unanimously by the 35-nation board strongly condemned Iran's past secret nuclear activities, especially the production of weapons-grade plutonium（钚）and enriched uranium.

Mr. ElBaradei described the main points of the document, "The resolution sets out a marker in terms of non-proliferation. It deplores in strong terms Iran's undeclared activities; it makes it very clear that Iran should cooperate fully and in a very transparent way in the weeks and months to come, and also makes it very clear that, should any serious failures come to light in the future, these will be taken by the board with the seriousness it deserves."

But the document also welcomed Iran's recent co-operation with the U.N. nuclear watchdog and Tehran's decision to suspend its uranium enrichment program. The United States maintains the enrichment program forms part of a secret plan by Tehran to build nuclear weapons.

The United States backed the resolution, even though it originally wanted Iran to be brought before the U.N. Security Council for possible sanctions.

Mr. ElBaradei says IAEA inspectors have a lot more work to do in Iran in the upcoming weeks before it concludes that Iran's nuclear program is for peaceful purposes, as Iran claims.

In Tehran, foreign ministry spokesman Hamid Reza Asefi called the resolution an achievement for the Islamic republic and victory for cooperation, politics and dialogue.