Iran has struck a historic deal with the United States and five other world powers, agreeing to a temporary freeze of its nuclear programme.
The agreement is the most significant between Washington and Tehran in more than three decades.
Iranian President Hassan Rouhani endorsed the agreement, which commits Iran to curb its nuclear activities for six months in exchange for limited and gradual sanctions relief, including access to $4.2billion dollars (£2.5bn) from oil sales. The six-month period will give diplomats time to negotiate a more sweeping agreement. It builds on the dialogue opened during September’s annual UN gathering and includes freezing Iran’s ability to enrich uranium at a maximum 5% level, which is well below the threshold for weapons-grade material.
Mr Obama hailed the pact’s provisions, which include curbs on Iran’s enrichment and other projects that could be used to make nuclear arms, as key to preventing Iran from becoming a nuclear threat.
“Simply put, they cut off Iran’s most likely paths to a bomb,” he said.
For Iran, keeping the enrichment programme active was a critical goal. Iran’s leaders view the country’s ability to make nuclear fuel as a source of national pride and an essential part of its insistence at nuclear self-sufficiency.
Giving up too much on the enrichment programme would have likely brought a storm of protest by Iranian hard-liners.
In a nationally broadcast speech, Mr Rouhani said the accord recognises Iran’s “nuclear rights”.
He added: “No matter what interpretations are given, Iran’s right to enrichment has been recognised.”