Kabul ( CNN ) -- U.S. Secretary of State John Kerry arrived in Austria on Sunday for talks with five other world powers and Iran on Tehran 's nuclear program . The participants will hold a final round of negotiations ahead of a July 20 deadline aimed at reaching a permanent deal on the future of Iran 's nuclear program . `` Obviously , we have some very significant gaps still , so we need to see if we can make some progress , '' Kerry said in the Austrian capital , Vienna . `` I really look forward to a very substantive and important set of meetings and dialogues . '' The nuclear talks will include the five permanent members of the United Nations Security Council -- the U.S. , UK , France , China and Russia -- and Germany . `` It is vital to make certain that Iran is not going to develop a nuclear weapon , that their program is peaceful , '' Kerry said . Tehran insists its ambitions are peaceful , but the world powers fear it plans to build nuclear weapons . `` We do n't see any benefit in Iran developing a nuclear weapon , '' Iran 's Foreign Minister Javad Zarif told NBC 's `` Meet The Press '' from Vienna . He said Iran has a number of advantages over its neighbors , including `` the fact that we have better technology , '' which Iran does n't need to augment with nukes . `` I believe nuclear weapons reduces countries ' influence in our region , '' he added . `` It does n't help anybody . '' Israel 's Prime Minister Benjamin Netanyahu , speaking on `` Fox News Sunday '' from Jerusalem , called Zarif 's comments a `` joke '' and a `` sham . '' He said Iran has invested billions into its nuclear program . `` For what ? For creating medical isotopes for Iranian patients circling the earth ? What are they developing ICBMs for if not for nuclear warheads ? '' he asked . `` What are they developing these -- building these enormous underground nuclear facilities , if not for a nuclear weapon ? '' Kerry is expected to meet with Zarif on Sunday night . Kerry seeks to mend U.S.-German relations . Kerry met Sunday in Vienna with his German counterpart , Frank-Walter Steinmeier . The encounter came amid a row over fresh spying allegations against the United States . On Thursday , Germany 's government asked America 's top spy chief stationed in the country to leave . This followed the revelation that two Germans -- one working at a German intelligence agency , the other in the Ministry of Defense -- are suspected of spying for the United States . After Sunday 's meeting , Kerry described the relationship between the two countries as `` a strategic one . We have enormous political cooperation , and we are great friends and we will continue to work together in the kind of spirit that we exhibited today . '' Kerry did not address the spy flap in his public remarks after the meeting , saying instead the conversation focused on Iran and also included Afghanistan and Iraq . Kerry : Afghanistan election audit coming . Kerry 's stop in Austria follows an unannounced visit to Afghanistan , where divisions are growing since the country 's contested presidential runoff election . After his visit , he announced that an audit of the disputed presidential election results will begin within a day in Kabul , and the two candidates will accept its determination of who won . The inauguration of the new president , originally scheduled for August , will be postponed during the audit of votes cast for Abdullah Abdullah and Ashraf Ghani , Kerry said . Provisional results showed Ghani ahead with roughly 56 % support to 43 % for Abdullah . Both candidates have alleged vote fraud and manipulation during the runoff last month .
NEW : Israeli Prime Minister says Iran is obviously trying to build nuclear weapons . Kerry says U.S. and Germany ` ` great friends '' amid the flap . Top Iranian leader says his country does n't need to build nuclear weapons . Kerry says it 's vital to ensure ` ` Iran is not trying to develop a nuclear weapon ''