By Jon Leyne
BBC News, Tehran
The former President of Iran, Hashemi Rafsanjani, has called on the West to engage in talks on the nuclear issue.
Mr Rafsanjani's comments contrast with those of the president
His plea is in marked contrast to defiant comments made by President Ahmedinejad earlier this week.
Mr Rafsanjani has just been voted head of Iran's Assembly of Experts - one of the most influential positions in the country's political system.
His comments suggest he may use his influence to challenge the hardline approach of President Ahmedinejad.
Mr Rafsanjani assured the West that Iran was not seeking a nuclear weapon.
The nuclear programme would be used in the service of humanity, he said. He urged the West to negotiate over the issue.
By contrast, earlier in the week, President Ahmedinejad proudly boasted about the progress in Iran's nuclear work and he mocked the West over its failure to prevent the programme.
However, he has also insisted it is purely for peaceful purposes.
In Iran's complicated and secret political system there is an ongoing battle for power behind the scenes, with the Supreme Leader, Ayatollah Khamenei, as the deciding force.
It is clear that right now President Ahmedinejad is facing tough competition from a number of directions.