The UN Security Council has broken a three-week diplomatic deadlock over Iran, calling on Tehran to cease parts of its nuclear programme and requesting the head of the International Atomic Energy Agency to report back in 30 days.

The breakthrough came ahead of a meeting on Thursday in Berlin between the foreign ministers of France, Germany, the UK, Russia, China and the US, which will discuss next steps.

The compromise presidential statement, agreed by the permanent five members of the Security Council and endorsed by the full fifteen, stressed ?the particular importance of (Iran) re-establishing full and sustained suspension of all enrichment-related and reprocessing activities, including research and development.?

It stepped back from five explicit demands made in an earlier draft, including access to individuals, documentation and nuclear sites. But diplomats said the statement implicitly endorsed them by calling on Tehran to take all steps previously stipulated by the IAEA Board.

Western officials ? including Condoleezza Rice, secretary of state, Jack Straw, UK foreign secretary, and Philippe Douste-Blazy, French foreign minister - spent almost a month lobbying Moscow and Beijing, which were worried the declaration might lead inescapably to sanctions or confrontation.

The final hurdle was a draft reference to the Security Council?s role in maintaining international peace and security ? an echo of the UN charter?s powerful chapter VII, under which the Council can authorise sanctions or military force.

Following Russian demands, that reference was dropped. The 30-day timetable for the report, which will go in parallel to the IAEA board, came after Russia objected EU and US calls for a two-week period.

Andrey Denisov, Russia?s UN ambassador, likened the process to a ladder. ?If you want to climb, you must step on the first step,? he said, citing very strong suspicions about Iran?s intentions.

John Bolton, the US ambassador, called the statement the ?first major step? in the Security Council to deal with Iran?s alleged weapons programme, and an ?unambiguous signal to Tehran that the Security Council is now dealing with this issue.?

But Wang Guangya, China?s ambassador, insisted the IAEA remained in charge, and that the Security Council statement represented political support for its deliberations. He said the council?s aim was to ?support all diplomatic efforts which will lead to a negotiated solution.?

Despite Wednesday?s deal, an EU diplomat warned: ?the process we have in front of us will be clearly considerably more difficult than what we have done already?, referring to the difficulty of agreeing a substantive UN security council resolution in the future. ?But since we have agreed a graduated approach each step has an importance in itself.?

?Sanctions is crunch time,? a senior state department official said of the next step in US efforts to persuade Europe to move further on Iran.