( CNN ) -- Negotiations aimed at curbing Iran 's nuclear ambitions may have stalled in Switzerland this weekend , but the head of the U.N. nuclear watchdog agency is optimistic about a new agreement struck with Tehran . The International Atomic Energy Agency signed a cooperation deal with Iran on Monday . It will give the IAEA greater access to long-unseen nuclear sites , including a heavy-water reactor in Arak , the very site that may have tripped up the Geneva talks . Yukiya Amano , the director general of the International Atomic Energy Agency , said the agreement signified a new willingness by Tehran to cooperate with the IAEA . `` The atmosphere is very different , the meeting was very constructive , '' he said in an interview with CNN 's Christiane Amanpour . `` This is an important step , but this is a first step , and much more needs to be done . '' He said the deal would take a step by step approach to solving problems , bearing in mind the complications in dealing with the Iranian nuclear issue . Amano said Iran and the IAEA have agreed to focus on six practical measures that would be implemented in a three-month time line . `` The joint statement says Iran and IAEA agree to resolve all present and past issues , '' Amano said . `` Issues that are not included in the first step will be addressed in the subsequent steps . '' The IAEA 's talks with Iran are separate from the big power diplomacy , he said , referring to the recent nuclear talks between world powers and Iran in Switzerland , which disintegrated on Sunday . Hopes for a deal had soared after top diplomats rushed to Geneva , but then faded amid divisions among the P5+1 countries . Representatives from Iran and those six countries are scheduled to meet again in Geneva on November 20 , in another attempt to resolve the decade long dispute . `` Geneva talks and IAEA talks are independent , different and separate , '' Amano said . `` We are focusing on verification and technical issues . '' State Department : `` We made significant progress in Geneva '' The IAEA chief has reason to be optimistic , given that this is his first agreement with Iran in years , said Joseph Cirincione , president of Ploughshares Fund , a public grant-making foundation focused on nuclear weapons policy and conflict resolution . `` This is for real , these guys are not playing a con game , '' Cirincione said . `` These Iranians are a much more pragmatic group . They want to make a deal , they want to end Iran 's isolation . They want to end sanctions . They are willing to make serious concessions . '' On Tuesday , the U.S. State Department also sounded upbeat , saying significant progress was made in Geneva . `` The P5+1 is united , '' said Jen Psaki , State Department spokesperson . `` There is still a gap between what language might be appropriate ; that the Iranians are prepared to accept . '' Iran has always insisted its nuclear program is for peaceful purposes . Western powers and Israel accuse it of harboring ambitions for a nuclear weapon . Iran 's refusal to stop enriching uranium has led to crippling sanctions that have stunted its economy , slashed its crude oil exports and triggered widespread inflation at home . U.S. senators from both parties have pushed for tougher sanctions to increase pressure on Iran even as the Geneva talks showed early signs of promise last week . But the White House warns lawmakers that tightening sanctions on Iran could derail the diplomatic push to curb Tehran 's nuclear program . Secretary of State John Kerry will push diplomacy as he heads to Capitol Hill on Wednesday to meet with members of the Senate Banking Committee . Some of the restrictions originated in that Banking Committee . The State Department said Kerry would make it clear that putting new sanctions in place would be a mistake . `` We are still determining if there is a diplomatic path forward , '' Psaki said . `` What we are asking for right now is a pause , a temporary pause , in sanctions . We are not taking away sanctions . We are not rolling them back . This is about ensuring our legislative strategy and our negotiating strategy are running hand in hand . '' `` The momentum for this deal is almost irresistible , '' said Cirincione . `` It may not happen November 20 . It may take a few more weeks , but it is crystal clear , the majority of P5+1 believe a deal is in our best interest . '' CNN 's Christiane Amanpour contributed to this story .
No results in weekend talks on Iran 's nuclear program . The United States and its allies are trying to persuade Tehran not to develop a nuclear weapon, but the Islamic Republic has said it will never give up its right to peaceful use of atomic energy. IAEA chief : ` ` This is an important step , but this is a first step ''