London ? Global criticism rained down on Iran on Tuesday after it broke seals set by the International Atomic Energy Agency on a nuclear enrichment facility in Natanz, ending a two-year freeze on activities that Western leaders fear could lead to the enrichment of uranium to build nuclear weapons.

In response, European ministers scheduled an urgent meeting for Thursday to determine whether to recommend that Iran face proceedings before the U.N. Security Council that could result in economic sanctions.

Several governments said the action by Iran’s new hard-line government led by President Mahmoud Ahmadinejad was unnecessary and provocative. While the Islamic Republic has insisted that it intends to use nuclear energy to operate only power generating plants, nations including the United States are convinced that Iran plans the research in order to develop nuclear weapons.

While breaking the seals is not, in and of itself, an illegal act, the IAEA, using its strongest language to date, voiced “serious concern” at Iran’s action. The IAEA is the body that oversees adherence to the Nuclear Non-Proliferation Treaty.

“There is no good reason why Iran should have taken this step,” said Foreign Minister Jack Straw of Britain, one of the three European countries negotiating with Iran to limit its nuclear program on behalf of the European Union.

Scott McClellan, the White House press secretary, called the move a “serious escalation” and said that if Iran “continues down this road and the negotiations have run their course, then there is only one option to pursue, and that is referral to the Security Council. And that is the option we are talking about with our European friends and others.”

“I think the international community is prepared to move to the next step,” McClellan warned.