"President Barack Obama welcomed the deal, saying it included "substantial limitations which will help prevent Iran from building a nuclear weapon".
Iran agreed to give better access to inspectors and halt some of its work on uranium enrichment.
President Rouhani said the interim deal recognised Iran's nuclear "rights".
But he repeated, in a nationwide broadcast, that his country would never seek a nuclear weapon.
Tehran denies repeated claims by Western governments that it is seeking to develop nuclear weapons. It insists it must be allowed to enrich uranium to use in power stations.
The deal will last for six months allowing time for the negotiation of a more permanent agreement."