World powers intensified nuclear talks with Iran yesterday , two days before a deadline for reaching a framework deal . The foreign ministers of the United States , France and Germany cancelled their travel plans for the next few days so they can push for the accord that would lay the foundations for a final settlement with Tehran by the end of June . U.S. Secretary of State John Kerry 's spokeswoman said he would not fly to Boston for a ceremony in honour the late Senator Edward Kennedy , who was his mentor . Officials close to the talks in the Swiss city of Lausanne also confirmed the French and German foreign ministers , Laurent Fabius and Frank-Walter Steinmeier , had cancelled a planned joint trip to Kazakhstan . Scroll down for video . World powers intensified nuclear talks with Iran yesterday , two days before the deadline for reaching a framework deal . Pictured from left : US Under Secretary for Political Affairs Wendy Sherman , US Secretary of State John Kerry , US Secretary of Energy Ernest Moniz and British Foreign Secretary Philip Hammond . 'We 're hopeful , but there is still a lot of work to be done , ' Fabius told reporters on Sunday . Iran denies charges from the West and Israel that it wants to build a nuclear weapon , and says its programme is purely peaceful . It wants the removal of international sanctions that are hurting its economy . The remarks from Fabius contrasted to a hostile blast from Israel , which is not a party to the talks between Iran and the six powers also including China , Russia and Britain . 'This deal , as it appears to be emerging , bears out all of our fears , and even more than that , ' Prime Minister Benjamin Netanyahu told his cabinet in Jerusalem . Israel , which is believed to have the Middle East 's only nuclear arsenal , feels especially threatened by the possibility of a nuclear-armed Iran . Netanyahu referred to advances made by Houthi rebels allied to Tehran in Yemen , and accused the Islamic republic of trying to 'conquer the entire Middle East ' . 'The Iran-Lausanne-Yemen axis is very dangerous to humanity , and must be stopped , ' he said . Strategic Affairs Minister Yuval Steinitz , the Israeli official who has been spearheading efforts to lobby world powers against the Iran deal , voiced cautious hope that the negotiations would collapse as they have in the past . 'There are still great doubts in the United States as well as in France , even in England , ' Steinitz told Israel Radio . US Secretary of State John Kerry , ( left ) will not fly to Boston for a ceremony in honour of his mentor , the late Senator Edward Kennedy . In the past , Israel has threatened to attack Iran if it is not happy with an eventual deal and has long described France as the negotiating power with views closest to its own . The six world powers are seeking a halt to Iran 's most sensitive nuclear work , settling a dispute that dates back more than a decade and has threatened at times to trigger a new Middle East war . Kerry and Iranian Foreign Minister Mohammad Javad Zarif have been in Lausanne for days to try to reach a preliminary deal by a self-imposed deadline of Tuesday . They held several rounds of talks on Saturday and met again on Sunday morning . Fabius and Steinmeier joined the talks on Saturday , and their counterparts from China , Britain and Russia were to take part later on Sunday . Close as the sides have come to the outline of an agreement , they still have deep disagreements on Iran 's demands for uranium enrichment research and the immediate removal of all U.N. and key U.S. and . European Union sanctions . Those disagreements could wreck a deal , officials say . Zarif says the six powers are now the ones who must compromise . 'In negotiations , both sides must show flexibility , ' Zarif said on Twitter . 'We have , and are ready to make a good deal for all . We await our counterparts ' readiness . ' Western officials close to the talks said it was up to Iran to compromise on the remaining sticking points . 'The serious but difficult work continues , ' a senior U.S. State Department official said . 'We expect the pace to intensify as we assess if an understanding is possible . ' A key point in the framework accord the sides are trying to agree by Tuesday is expected to be the duration of the agreement , which officials from the six-power group said would have to be in place for more than 10 years . The framework accord should be followed by a comprehensive deal by June 30 that includes full technical details .
Foreign ministers of the United States , France and Germany cancelled travel plans for the end of June . Aim to push for accord that would lay foundations for final settlement with Tehran by the next few days . Iran denies charges from the West that it wants to build nuclear weapon . It wants removal of international sanctions that are hurting its economy .