President Obama has hailed a deal restricting Iran's nuclear programme as an "historic understanding" which, if implemented, will make the world safer.
The framework agreement, struck after intensive talks, aims to prevent Tehran making a nuclear weapon in exchange for phased sanction relief.
Iran and the six world powers involved must now finalise the deal.
Iranians have been celebrating in the streets but Israel says the deal threatens its survival.
But most world leaders have welcomed the deal, and the U.S. President said it would be long-term.
