Iran nuclear deal 'possible this week', says Kerry

US Secretary of State John Kerry is optimistic that a deal with Iran over its nuclear programme could be reached within the week

An agreement on a deal with Iran on its disputed nuclear programme could be sealed this week, US Secretary of State John Kerry says.

He was speaking to reporters in Vienna, where Iran is negotiating with the US and five other world powers.

But Kerry also warned that the two sides were "not where we need to be on several of the most difficult issues".

Negotiators face a 7 July deadline. Iran's foreign minister said on Friday that a deal had never been closer. "If hard choices get made in the next couple of days and made quickly, we could get agreement this week," Kerry said.

Over the past few days, "genuine progress" had been made, he added.

But the US was prepared to walk away "if we don't have a deal and there is absolute intransigence and unwillingness to move on the things that are important".