Iran's decision to temporarily suspend its uranium enrichment activities is being quietly welcomed in European capitals, but diplomats say a long-term agreement aimed at neutralizing fears that Iran aims to make a bomb could take several months.

Diplomats in Brussels who have been monitoring the negotiations in Tehran say the agreement for Iran to suspend its uranium conversion activities in exchange for political and economic incentives from Europe's Big Three is still a work in progress.

They say the most immediate consequence of the deal is that Iran will probably escape the threat of sanctions when the International Atomic Energy Agency's board of governors meets in Vienna next week to discuss what the United States and other critics of the regime in Tehran say is a nuclear weapons program.

Iran says its move to suspend uranium enrichment pending a longer-term accord with the Europeans is a voluntary move and not a legal obligation. It says uranium enrichment activities will remain suspended for as long as talks continue with Britain, France and Germany on the broader issue of what incentives they are prepared to offer Iran.

A senior European Union diplomat says the basic accord was negotiated last week in Paris but that details were hammered out in Tehran on Saturday and Sunday.

Iranian nuclear negotiator Hossein Moussavian says he is happy at the outcome of the talks.

"The Paris agreement is a win-win situation for both of us," said Mr. Moussavian.

Under the deal, if Iran's suspension of enrichment activities is verified, the European Union must resume negotiations with Iran on a trade and cooperation agreement, and support the opening of talks on Iran's accession to the World Trade Organization.

A report by the International Atomic Energy Agency, which will be tasked with verifying Iran's compliance with the accord, said Monday that none of the nuclear materials declared by Iran have been diverted to make weapons. But the agency says it does not know whether undeclared nuclear material could have been used for a weapons program.

Analyst Martin Navias, a senior fellow at King's College in London, is skeptical about Iran's intentions.

"I believe that the Iranians have made a strategic decision to acquire weapons of mass destruction, and no parcel of sticks or carrots will convince them otherwise," said Mr. Navias. "I believe the Iranians are playing for time and that, ultimately, they will continue to develop weapons of mass destruction. I believe we are heading for a crisis with Iran in the next 18 months."

EU diplomats, while wanting to avoid a confrontation with Tehran, acknowledge that it will take months for IAEA monitors to finish investigating Iran's nuclear program and be able to certify that the country no longer has hidden or undeclared nuclear activities.