When the US secretary of state and his Iranian counterpart announced to the world they reached the basis of a nuclear deal, many welcomed the news.
But barely a week later, the tone has changed.
Iran's Supreme Leader Ayatollah Ali Khamenei says there is no "guarantee" the agreements reached in Switzerland will lead to a final deal with world powers.
And in a sign of the hurdles that lie ahead for negotiators, all sanctions would need to be lifted as soon as a deal is reached, the ayatollah says.
The US says its position has always been, that sanctions would be lifted gradually, to ensure Iran follows through with its commitments to reduce its uranium stockpile.
But the remarks by the Iranian supreme leader show world leaders may not be as close to a final agreement as they had led people to believe.
So has this agreement been oversold? Or, are all sides just manoeuvring ahead of a final deadline in June?
Presenter: Sami Zeidan
Foad Izadi - Professor of World Studies at the University of Tehran.
Ali Vaez - Senior Iran Analyst at the International Crisis Group.
Mehdi Khalaji - Libitzky Family Fellow at the Washington Institute.
Source: Al Jazeera