VIENNA - Iran talks have now entered the ‘final’ extension and have to conclude within 48 hours, a Western diplomat said Tuesday in Vienna.

‘The talks are not ‘without any deadline’ or ‘open-ended’. We have just done the final extension,’ the diplomat said on condition of anonymity. ‘It’s difficult to see why and how we could go on any longer. Either this works in the next 48 hours or it doesn’t,’ the envoy said.

This was echoed by a second Western diplomat, who said that the talks were ‘not an open-ended process’. ‘We’ve given ourselves a couple more days because we think it can be done,’ the second envoy said on condition of anonymity. Earlier Tuesday Iran and the P5+1 group - the United States, Russia, China, France, Britain and Germany - effectively gave themselves until Friday to agree a deal by extending the terms of a 2013 interim accord. An Iranian spokesman told AFP however that for his delegation, ‘we have no deadline.’ If US Secretary of State John Kerry, in Vienna since June 27, fails to hand over a deal by late Thursday, US lawmakers will get 60 days instead 30 to review it, which risks further complicating its implementation. The deal would curb Iran’s nuclear programme for a decade or more in order to make any push to make nuclear weapons - it denies any such aim - virtually impossible. In return painful sanctions on Iran would be progressively lifted.

Moreover, Iran urged global powers late Tuesday to drop a UN ban on arms sales to the country, describing it as an obstacle to a deal that was now in its final stages.

The arms embargo was not overly important as Iran had developed its own industry but global powers ‘must change their approach on sanctions if they want a deal,’ Iran’s Abbas Araghchi said on state television, adding the final text and most of the annexes were ‘almost finished.’ moreover, resolving the final issues in a mooted nuclear deal between Iran and major powers is proving ‘very, very, very tough’, a senior Western diplomat said Tuesday at tense talks in Vienna.

‘Removing the remaining brackets (in the text of the agreement), this seems to be very, very, very tough,’ the diplomat said. ‘This is not an open-ended process. We’ve given ourselves a couple more days because we think it can be done.’ Iran talks have now entered the ‘final’ extension and have to conclude within 48 hours, a Western diplomat said Tuesday in Vienna. ‘The talks are not ‘without any deadline’ or ‘open-ended’. We have just done the final extension. It’s difficult to see why and how we could go on any longer. Either this works in the next 48 hours or it doesn’t,’ the diplomat said on condition of anonymity. Global powers wrestling for a deal to curtail Iran’s suspect nuclear programme failed to meet another deadline Tuesday, with all sides vowing to now keep working until the end of the week.

‘We are continuing to negotiate for the next couple of days,’ EU foreign policy chief Federica Mogherini told reporters during a break in negotiations in Vienna.

But the United States said the terms of a November 2013 interim accord under which Iran has been cutting back its stock of enriched uranium in return for sanctions relief would be extended until Friday, July 10, meaning this is the effective new deadline.

‘We have never been closer, than we’ve ever been on this agreement, and we are still not where we need to be to finalise a deal,’ a senior US administration official said. Negotiators were taking the talks ‘day by day’ as they seek to slot into place the last pieces of a complex negotiation which has lasted almost two years now to deny Iran a nuclear bomb in return for sanctions relief. It was the fifth time since 2013 - and the second time in this round of talks - that negotiators have missed their own target date as talks have bogged down.

Mogherini insisted though it was still possible to overcome the remaining differences and reach a deal to draw a curtain on a 13-year standoff with Iran. US Secretary of State John Kerry is remaining in Vienna with Mogherini and their Iranian counterpart Mohammad Javad Zarif. Their Russian and Chinese counterparts had already left.

‘I think there is a clear will on both sides now to complete this agreement and to keep at it until we get there,’ said British Foreign Secretary Philip Hammond before also flying home for 24 hours for budget talks. After talking deep into the night Monday, foreign ministers from the so-called P5+1 - Britain, China, France, Germany, Russia and the United States - met three times Tuesday without their Iranian counterparts.

‘If very tough political decisions, hard choices, can get made soon, I do believe we can get to an agreement it is possible,’ the US official said. For many observers July 9 had always been the real deadline, and the US team now has its back against the wall trying to nail down the final details by then. If Kerry fails to hand over a deal by late Thursday, US lawmakers will get 60 days instead 30 to review it, which risks further complicating its implementation. Despite progress on a series of complicated annexes, negotiations have stalled on how to ease sanctions against Iran, probing allegations that in the past Tehran sought to develop nuclear arms, and ensuring Iran can continue to have a modest, peaceful nuclear programme. Russian Foreign Minister Sergei Lavrov confirmed there was also disagreement over the issue of lifting of a UN conventional arms embargo which bans sales of convention weapons such as tanks and missiles to Tehran.

‘I can assure you that there remains one major problem that’s related to sanctions: this is the problem of an arms embargo,’ Lavrov told Interfax from Vienna. Iran has urged that the UN arms embargo be lifted. But US officials insisted there would be ‘ongoing restrictions on arms just like there will be ongoing restrictions regarding missiles’ in any nuclear deal, which is to be endorsed by a resolution in the UN Security Council.

Negotiators are already drawing up a draft resolution which would also address the nuclear-related bans on arms trade and ballistic missiles, the senior administration official said. While Iran has a right to conventional missiles ‘what we are concerned about is missile techology that becomes a delivery system for a nuclear weapon.’