TEHRAN (Iran News) – Setting Iran deadlines to reach an explanation about alleged radioactive material found at a site in Iran could be counterproductive, the new UN nuclear watchdog chief said, hoping the fresh dialogue will resolve the issue.

“To put deadlines might not be the best idea,” Rafael Grossi told Reuters in an interview when asked how long he was willing to give Iran to provide an explanation that holds water on the particles of processed but not enriched uranium that IAEA inspectors say they have found at a warehouse near Tehran.

“This would for me mean that we would be in a very … an antagonistic relationship where basically one side would be resisting and then I as DG would need to be putting deadlines,” he said, adding, “We need to work together … Time is always of the essence.”

Grossi, a 58-year-old career diplomat from Argentina, took over as director-general of the International Atomic Energy Agency on Tuesday.

Grossi, a veteran of nuclear diplomacy who worked as a senior IAEA official from 2010 to 2013, has said he already knows some of the main decision-makers in Iran, but he has yet to meet senior Iranian officials since taking office.

He hopes he can help set a new tone with the Islamic Republic in his first face-to-face talks, starting this week on the sidelines of a meeting in Vienna of parties to Iran’s landmark 2015 nuclear deal with world powers. Iran’s delegation is usually led by Deputy Foreign Minister Seyyed Abbas Araqchi.

“I’m the new kid on the block in this relationship. They’ve been there, now they get a new DG, so we have to sit down together, start talking and take it from there,” he said.

“Let me start my conversation with Iran. I don’t think it would be appropriate, and it would be unfair, to pronounce myself about their attitudes before I sit down with them.”

Grossi has said he will be “firm but fair” on inspections generally, including in Iran, without spelling out what that means. He said he is satisfied with the work the IAEA’s inspections team has been doing.

While he has said he plans to communicate more actively than his late predecessor Yukiya Amano, he said that, like Amano, he would not voice an opinion on the state of the nuclear deal, which is on the verge of collapse since a US pullout from the accord last year and reimposition of sanctions on Iran.

Instead, the IAEA will stick to providing technical updates on Iran’s nuclear activities.