(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.
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No results in weekend talks on Iran's nuclear program
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But International Atomic Energy Agency hopes for better luck with deal signed Monday
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IAEA chief: "This is an important step, but this is a first step"
"Geneva talks and @placeholder talks are independent, different and separate," Amano said.