Major powers meet today to discuss imposing tougher UN sanctions against Iran unless it halts uranium enrichment work the West suspects is part of a secret programme to build nuclear weapons.
The United Nations has already imposed limited sanctions after Iran rejected resolutions ordering it to freeze the work. Iran says its nuclear programme is purely for electricity to benefit its economy, particularly to export more oil and gas.
Political directors from the five permanent UN Security Council members - the United States, Britain, France, Russia and China - plus Germany will discuss Iran on the sidelines of a Group of Eight (G8) meeting in Berlin.
"Among other things, they will discuss possible language for a new UN Security Council resolution on Iran," a diplomat from one of the six powers said on condition of anonymity.
China would participate in the meeting via telephone, diplomats said. US Under Secretary of State Nicholas Burns will represent the United States at the talks where delegates will discuss a recent meeting between European Union foreign policy chief Javier Solana and Iranian nuclear negotiator Ali Larijani.
Mr Solana said earlier this week his talks with Mr Larijani were very difficult as Iran had said it had no intention of suspending uranium enrichment.