Tehran, Iran ? Iran said Saturday it is likely to resume uranium enrichment-related activities within a week, a process it halted last year to build confidence in talks with European countries and avoid referral to the U.N. Security Council for possible sanctions.

Tehran’s announcement came a day after talks in London with European negotiators yielded no results. France, Britain and Germany, acting on behalf of the 25-nation European Union, are seeking guarantees from Iran that it will not use its nuclear program to make weapons, as Washington suspects.

Top Iranian nuclear negotiator Hasan Rowhani was quoted as saying Tehran expects to restart enrichment activities — injecting uranium gas into centrifuges — at its uranium conversion facility in Isfahan.

“It’s unlikely that uranium enrichment … which takes place in Natanz, will be resumed, but it’s likely that some activities at Isfahan Uranium Conversion Facility will restart next week,” IRNA quoted Rowhani as saying Saturday.

The central cities of Natanz and Isfahan house the heart of Iran’s nuclear program. The Isfahan conversion facility reprocesses uranium ore concentrate into gas, which is then taken to Natanz and fed into the centrifuges for enrichment.

In Vienna, Austria, a senior diplomat close to the International Atomic Energy Agency said the U.N. nuclear watchdog body had not been informed as of Saturday afternoon of Tehran’s intention. The official spoke on condition of anonymity.

The Europeans want Iran to permanently abandon enrichment, a process that can produce nuclear reactor fuel and, when taken to a higher level, material for bombs. In return, it is offering Iran economic aid, technical support and backing for Tehran’s efforts to join international organizations.

Washington last month agreed to support the EU effort but signaled that Iran should quickly accept it or face harsh Security Council sanctions. Iran insists its nuclear program is entirely peaceful and for generating electricity.