Iran says it has informed the United Nations nuclear agency of its decision to resume sensitive nuclear activities, since the European Union has failed to respond in time to its offer of new talks.

The spokesman for Iran's Supreme National Security Council, Ali Agha Mohammadi, told state media Monday that Iran has asked International Atomic Energy Agency inspectors to break the seals on its Isfahan nuclear plant, so technicians can resume work.

The plant in central Iran converts uranium ore into gas, a processing stage that precedes "enrichment," in which uranium is concentrated into a form suitable for weapons use. Iran agreed to suspend all uranium processing last November, under international pressure, but when Tehran announced it was reopening the Isfahan plant this week, officials promised there would be no production of enriched uranium.

Britain and Germany, which have been negotiating with Iran along with France, are urging Tehran not to take any unilateral action that could jeopardize talks over its nuclear program. The European Union intends to offer Iran economic and political incentives in exchange for permanent suspension of its uranium-enrichment activities.

The United States contends Iran is trying to build nuclear weapons. Tehran says its nuclear-energy program is entirely devoted to peaceful purposes.

Some information for this report provided by AP, AFP and Reuters.