US Secretary of State John Kerry has backed further diplomacy with Iran over the Islamic Republic’s uranium enrichment programme on a visit to the UAE on 11 November.

Kerry’s visit came after the P5+1 group and Iran failed to reach an agreement in nuclear negotiations in Geneva, although significant progress was reported by both sides.

“We were actually extremely close [to reaching a deal],” he told the BBC in an interview in Abu Dhabi. “I think we were separated by four or five different formulations of a particular concept. But none so terribly that I don’t think it’s possible to be able to reach agreement.”

Kerry has claimed Iran was unable to accept the proposal on the table “at that particular moment”, when it was presented in Geneva on 9 September.

However, Iran’s foreign minister, Mohammed Javad Zarif, has since rejected this claim, blaming the failure to agree a deal on divisions between the Western governments.

According to media reports, France was concerned about the eventual status of the Arak heavy water reactor, with the country’s foreign minister, Laurent Fabius, saying he was not prepared to accept a “fool’s game”.

“Arak has elicited particular alarm because it could be eventually used to produce plutonium and provide Iran with a second path to a nuclear weapon,” Barclays Capital analyst Helima Croft said in a research note.

“Moreover, once it becomes operational in the summer of 2014, it will be difficult for outside powers to use military force to disable the facility without triggering very adverse environmental consequences,” she added.

Representatives from the P5+1 – the US, UK, France, Russia, China and Germany – are set to meet with their Iranian counterparts again on 20 November.

“The hardest part of this comes after the first step,” Kerry said in Abu Dhabi. “But I was pleased with the amount of work done and we will just continue to work. That’s the nature of diplomacy.”