WASHINGTON: A few hours after the deal was clinched, US President Barack Obama told his nation his government had managed to `halt the progress of the Iranian nuclear programme`.

`Today that diplomacy opened up a new path towards a world that is more secure a future in which we can verify that Iran`s nuclear programme is peaceful and that it cannot build a nuclear weapon,` he said while presenting the deal as a major diplomatic achievement of his administration.

`While today`s announcement is just a firststep, it achieves a great deal. For the first time in nearly a decade, we have halted the progress of the Iranian nuclear programme, and key parts of the programme will be rolled back,` Mr Obama said.

`Iran cannot install or start up new centrifuges, and its production of centrifuges will be limited. Iran will halt work at its plutonium reactor. And new inspections will provide extensive access to Iran`s nuclear facilities and allow the international community to verify whether Iran is keeping its commitments, Mr Obama added.