BRUSSELS: The European Union's foreign policy chief Catherine Ashton told Iran on Friday to abandon its expressed intention to speed up nuclear work, saying that it would violate the Islamic republic's international obligations.

Iran has announced plans to install and operate advanced uranium enrichment machines, in what would be a technological leap allowing it to significantly speed up activity the West fears could be put to developing a nuclear weapon.

"Should Iran decide to install advanced centrifuges, this could significantly increase the production of enriched material and add to the already severe concerns ... about the exclusively peaceful nature of Iran's nuclear programme," Ashton's spokeswoman said.

Iran denies its work has any military intention and says it needs a nuclear programme for research and energy purposes.

France and Britain echoed Ashton's concerns, with a French foreign ministry spokesman saying the Iranian announcement was a "negative signal" ahead of possible negotiations between Tehran and six world powers over the disputed work.

Ashton is overseeing contacts with Iran on the issue on behalf of France, Britain, Germany, China, Russia and the United States, and has asked Iran to hold a round of talks this month.