Iran (search) said it will extend its suspension of uranium enrichment (search) until the end of July to give European negotiators time to prepare a proposal it can accept, but Tehran also warned against wasting the opportunity to strike a deal.

The announcement Sunday followed Iran's agreement last month to review a European Union (search) proposal for a new round of negotiations in the summer. Tehran's decision injects some breathing space into the international crisis over its nuclear program, at least temporarily.

"The Europeans have time up to the end of July to prepare details of their proposal," said Ali Aghamohammadi, a spokesman for Iran's Supreme National Security Council.

"To make Iran's nuclear facilities active in a proper way, both sides should work toward providing guarantees," Aghamohammadi was quoted as saying by the official Islamic Republic News Agency.

Europe sees suspension of uranium enrichment by Tehran as a precondition for further talks. No date has been set for the summer negotiations.

Iran suspended enrichment last November under international pressure led by the United States. Iran maintains its program is peaceful, but the EU and the United States fear the program is being used to develop nuclear weapons in violation of the Nuclear Nonproliferation Treaty.

Six months of talks with Europe have made no progress on the key point of contention — Iran's insistence on the right to enrich uranium and European opposition to such plans. And Iran threatened in May to restart some uranium reprocessing activities, the stage that precedes actual enrichment of uranium.

Enriched uranium can be used to produce warheads, but it also can be used in the production of electricity, which Iranian officials insist is the sole purpose of their nuclear program.

Iran has said repeatedly that its November decision to suspend all uranium enrichment-related activities was voluntary and temporary. The Europeans have been offering economic incentives in the hope that Iran will make it permanent.

Aghamohammadi called on the Europeans to firm up the agreement reached between Iran and the Europeans last November in Paris, which committed Tehran to suspension of enrichment and all related activities while the two sides discuss a pact meant to provide Iran with EU technical and economic aid and other concessions. Since then, the two sides have sparred over the exact terms of the agreement.

France, Britain and Germany, acting on behalf of the 25-nation EU, want Tehran to abandon its enrichment activities in exchange for economic aid, technical support and backing for Iran's efforts to join the World Trade Organization.

Efforts to resolve the crisis got a boost last month when the World Trade Organization (search) agreed to open membership negotiations with Iran — a move widely seen as an immediate reward for Tehran's decision to stick with talks with Europe.

Iran first applied to join the WTO in 1996, but the United States blocked its application 22 times. The United States said in March it would drop its veto, after consultations with France, Germany and Britain.

The United States has been skeptical of Europe's approach to Iran's atomic program, although of late President Bush has struck a gentler note. Last week he insisted that Europe-led talks with Iran "are making some progress" and defended his decision to allow Iran to apply for WTO membership as a key, but measured, step to advance those discussions.

The EU has threatened to take Iran to the U.N. Security Council for possible sanctions if it resumes uranium reprocessing. Tehran says it won't give up its right to enrichment but is prepared to offer guarantees that it is not seeking to build nuclear weapons.