Each side must accept "both the spirit as well as the letter" of a November 7 agreement, reached in Paris, under which Iran pledged to suspend all uranium enrichment activities, British Foreign Secretary Jack Straw told reporters.

Straw, along with German and French foreign ministers Joschka Fischer and Michel Barnier, as well as EU foreign affairs chief Javier Solana, met with top Iranian nuclear negotiator Hassan Rowhani to discuss the Paris agreement, EU officials said.

The accord, endorsed by the UN watchdog International Atomic Energy Agency (IAEA), promises Tehran trade, technology and security rewards in return for fully suspending enrichment, a crucial fuel-making process that can also be used to make atomic weapons.

Diplomats said the talks could not succeed unless Washington eventually took part, since Iran could not join the World Trade Organization (WTO), for example, or receive regional security guarantees without US support.

The United States, which charges that Iran is using the Paris agreement to gain time to enable it to secretly develop nuclear weapons, has not yet supported the EU initiative with Iran but is not opposing it.

The EU negotiators from Britain, France and Germany had refused at an IAEA meeting in Vienna last month to let Iran withhold 20 centrifuges -- the machines that enrich uranium -- from the freeze in order to do research, saying the halt must be total and involve all related enrichment activities.

The Iranian demand had threatened to scupper the agreement.

"We'll be discussing ... the full implementation of the Paris agreement," Straw said, adding: "The words of the Paris agreement mean what they say."

But in Tehran, government spokesman Abdollah Ramazanzadeh said Iran was sticking to its demand that 20 centrifuges be excluded. "The question of halting research is not on the agenda," he said.

Straw said the European trio and Iran would be setting up "three working groups to take forward the Paris agreement."

The working groups cover incentives Iran is to be offered over the long term. One group is in technology, economics and cooperation, another in nuclear issues and a third in politics and security, diplomats said.

In return for "objective guarantees" that it will not develop the bomb, Iran has been offered incentives such as help in joining the WTO and in obtaining a light water research reactor. Tehran would in turn abandon plans to build a heavy water reactor that would be more capable of producing bomb-grade material.

The working groups were to meet later Monday at the Iranian embassy after the ministers' meeting, an EU official said, adding that Iranian-EU discussions on a trade and cooperation agreement would probably take place in January.

"This process is going to take off today," a senior European diplomat told AFP, adding that it would take "a bit longer" than the three-month deadline the Iranians have set.

The road is fraught with difficulties since Iran says its suspension of uranium enrichment is a temporary measure designed to show its intentions are peaceful, while the EU negotiators want it to become permanent, diplomats said.

The IAEA has been investigating Iran's nuclear programme for almost two years.

Iran said Sunday that it was not prepared to accept a permanent freeze as it claims it has the right to enrich uranium under the nuclear Non-Proliferation Treaty.

Rowhani warned that the Islamic republic would abandon the talks, and the suspension, in the absence of meaningful progress.

The IAEA had on November 29 decided against referring Iran to the UN Security Council for threatened sanctions, as the United States wants, after Tehran agreed on the suspension.

In a sign of continuing concern about Iran's intentions, diplomats said last week that the Islamic Republic was conducting secret high-energy neutron experiments, allegedly taking place under military supervision, that could be destined for civilian purposes or aimed at making nuclear weapons.

All rights reserved. © 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.