Iran and six world powers meeting in Geneva on Sunday reached a deal that temporarily freezes Tehran’s nuclear programme and marks a historic first step toward a more permanent agreement.

US President Barack Obama said with the 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”.

The deal was announced at 3 am on Sunday in Geneva where officials from Iran and the P5+1 - the US, Britain, Russia, France, China and Germany - along with the European Union -held three days of intensive negotiations.

“Today, that diplomacy opened up a new path toward 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,” Obama said in Washington.

Under the deal, which will last six months giving time for negotiators to reach a comprehensive agreement, Iran will roll back key aspects of its nuclear programme.

Iran’s Foreign Minister Mohammad Javad Zarif said his country had not given up the right to enrich uranium.

But Iran has committed to halt uranium enrichment above 5 per cent, which is sufficient for energy production but not for making a bomb. Further, it will neutralise its stockpile of near-20 per cent enriched uranium; halt progress on its enrichment

capacity; make no further advances of its activities at the Arak reactor; halt work at its plutonium reactor; and give International Atomic Energy Agency inspectors daily access to monitor its nuclear facilities at Natanz and Fordow.

The White House said these measures will help prevent Iran from using the cover of negotiations to continue advancing its nuclear programme. “These are substantial limitations that will help prevent Iran from building a nuclear weapon. Simply put, they cut off Iran’s most likely paths to a bomb,” Obama said.

In return, the P5+1 nations will provide Iran $7 billion in sanctions relief. But the sanctions on the export of petroleum products by Iran, which have forced countries such as India to significantly reduce their Iranian oil imports, will remain in effect.

Sanctions on banking will also remain.

In the US Congress, members are considering imposing tough new sanctions on Iran. Obama said doing so would “derail this promising first step, alienate us from our allies, and risk unraveling the coalition that enabled our sanctions to be enforced in the first place”.

Obama said the “broader architecture” of sanctions will remain in place and will be vigorously enforced. “If Iran does not fully meet its commitments during this six-month phase, we will turn off the relief, and ratchet up the pressure,” said the US President. The negotiations over Iran’s nuclear programme have strained ties between the US and Israel.

Israeli Prime Minister Benjamin Netanyahu called the deal a “historic mistake”.

“Today the world became a much more dangerous place because the most dangerous regime in the world made a significant step in obtaining the most dangerous weapons in the world,” Netanyahu said. Obama acknowledged that Israel and some Gulf countries - a reference to Saudi Arabia - “have good reason to be skeptical about Iran’s intentions”.

A senior US official said the agreement with Iran aimed to address a number of concerns that Israel had expressed over the years; and speaking in Geneva, Secretary of State John Kerry said the deal would make Israel safer. The breakthrough with Iran follows the election of Hassan Rouhani as President of the Islamic republic in August. The Associated Press reported on Sunday that the US and Iran had held a series of secret meetings in the months preceding Rouhani’s election.

An Indian American, Puneet Talwar, has played a prominent role in those back-channel talks.

Talwar is the National Security Staff senior director for Iran, Iraq, and Persian Gulf affairs.

Deputy Secretary of State William Burns and Jake Sullivan, deputy assistant to Obama and national security adviser to Vice President Joe Biden were also key players in the initial diplomacy.

Rouhani said on Sunday that Iran would never seek nuclear weapons.

Obama, who spoke at the White House later on Saturday night, said the burden was on Iran to prove to the world that its nuclear programme would be exclusively for peaceful purposes.