"We continue to make progress, but there is still a substantial amount of work to be done," said the official, who spoke on the condition of anonymity to discuss the difficult and secretive negotiations. Zarif and Kerry conferred, ahead of a fresh round of negotiations between Iran and six world powers in Geneva, on settling their 12-year standoff over Tehran's nuclear ambitions. Lower-level negotiators on both sides met at the same venue on 15 January 2015 to iron out technical details ahead of negotiations 3 days later between Iran and the "P5+1" powers – the US, France, Germany, Russia, China and Britain. Speaking at a Tehran news conference, Zarif said the purpose of the talks with Kerry "is to see if we can speed up and push the negotiations forward". In February, Zarif said that Iran did not favor another extension of the talks on limiting its nuclear program and expected economic sanctions to be quickly lifted if an accord was reached. At a security conference in Munich, he said "Sanctions are a liability; you need to get rid of them if you want a solution." Of the long effort to forge an agreement, he said "This is the opportunity to do it, and we need to seize this opportunity. It may not be repeated." The nuclear talks have already been extended twice and face a late March deadline for working out the main outlines of an accord. The deadline for a detailed agreement is the end of June. Based on the Iran nuclear deal framework, which was declared on 2 April, Iran agreed to accept significant restrictions on its nuclear program for at least a decade and submit to international inspections under a framework deal. In return, international sanctions would be lifted; whether in phases or all at once still needed to be worked out. Nuclear agreement On 21 November it was reported by Iranian negotiators that progress was being made in talks in Geneva with world powers, expressing hope to bridge differences and sign an elusive deal over Tehran's nuclear drive. In statements carried by Iranian media after a one-hour meeting with Baroness Ashton, Zarif said "Differences of opinion remain and we are negotiating over them. God willing we will reach a result." Three days later, the Geneva interim agreement, officially titled the Joint Plan of Action, was signed between Iran and the P5+1 countries in Geneva, Switzerland.