Negotiations¹ connected to Iran's nuclear program have resumed² in Switzerland.

US Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif have sat down for the first of what should be three days of meetings in the Swiss city of Montreux.

Speaking ahead of the talks, Kerry notes there is still no deal in place.

"Right now no deal exists, no partial deal exists, and unless Iran is able to make the difficult decisions that will be required there won't be a deal. Nothing is agreed until everything is agreed."

At the same time, Kerry is also cautioning³ Israel not to undercut the negotiations.

"We are concerned by reports that suggest selective details of the ongoing⁴ negotiations will be discussed publicly in the coming days. I want to say clearly that doing so would make it more difficult to reach the goal that Israel and others say they share in order to get a good deal."

Iran and the P5+1 have until the end of March to reach a political agreement, with a further four months to work out the technical aspects of any deal.

The negotiations have already missed two previous deadlines.