The Isfahan facility is used to convert raw uranium into a gas that can be fed into enrichment centrifuges. Tehran says it had already converted 37 tons of raw uranium into gas before its suspension came into force.
Iran agreed in November to suspend all uranium-enrichment activities in order to reach a permanent deal with Great Britain, France, and Germany aimed at ensuring the international community that Tehran is not pursuing the development of nuclear weapons.
Iran says its nuclear program is peaceful, while the United States accuses the country of secretly developing nuclear weapons. Enriched uranium can be used in the production of nuclear bombs.
In recent months, Iranian officials have expressed discontent with the slow pace of talks with the so-called EU-3, who promise trade and other benefits if Iran gives assurances that it is not seeking to produce nuclear weapons.
But the negotiations have been dragging, with Iran saying it will never give up uranium enrichment and insisting that it has the right to pursue a peaceful nuclear energy program.
The last round of Iran/EU talks ended in London in March inconclusively. Since then, in a sign of growing frustration and impatience, several Iranian officials have said that some frozen nuclear activities will be resumed without giving any specific date.
Mehdi Mozaffari, a professor of political science and international relations at Aarhus University in Denmark, told RFE/RL that he believes Iran is attempting to gain the upper hand in its dealing with France, Britain, and Germany.
"It is true that in recent week there is an apparent change in comments by Iranian officials and it shows that the Islamic Republic -- which was in a state of defense -- is trying to become more aggressive," Mozaffari said. "And it seems that they have come to the conclusion that such a method will not have a heavy price for them and at the same time more time can be gained. And they are also trying to take the initiative in their hands , because before it was in the hands of the Europeans after the IAEA [International Atomic Energy Agency]."
On 4 May, Iranian President Mohammad Khatami said Tehran might decide to resume certain activities. However, he added that these activities do not yet include enrichment and that Iran is determined to continue the talks with the EU countries.
"We have not announced the end of the negotiations, we will negotiate," Khatami said. "It is possible that we will decide to resume some activities that are very far away from enrichment, but I have to say that our aim is to continue the negotiations and whenever it is necessary and our European friends are ready, these talks will continue with the [IAEA]."
Despite similar comments from Iranian authorities, EU officials have warned that a resumption of suspended activities would constitute a breach of the November deal. Last week, German Foreign minister Joshka Fischer said any resumption of enrichment activities would lead to a collapse of the talks.
Yesterday, acting State Department spokesman Tom Casey said any move by Iran to resume activities such as preparation of uranium for enrichment would be in clear violation of its agreement with the EU-3. He warned Iran against the consequences of such a violation, without elaborating. U.S. officials had said before that Iran's nuclear dossier should be referred to the UN Security Council for possible sanctions.
However, professor Mozaffari says that such process could take months. "If the Islamic Republic resumes some of its past [nuclear] activities in Isfahan it will face international [condemnation] but in the first stage there will be statements and oral protests," he said. "Then the EU and U.S. should become united and the issue should be brought up in the June [IAEA] meeting. And then the decision to refer Iran to the Security Council should be adopted. And then -- if it goes to the Security Council -- it is not clear if a resolution will be adopted and will not face a veto by Russia or China. Because of this, it seems that Iranian authorities have come to the conclusion that they can still play games."
Today EU High Representative for the Common Foreign and Security Policy Javier Solana said he favors transferring the case of Iran's nuclear activities to the IAEA if talks break down between Iran and the EU. Iran's nuclear program will be discussed at the IAEA board meeting in June.
The IAEA has not reacted yet to Tehran's announcement yesterday that it will resume some frozen nuclear activities. On 2 May, IAEA Director-General Muhammad el-Baradei called on Iran and the European Union to keep their nuclear talks alive and urged Tehran to refrain from uranium enrichment.