A senior official of the International Atomic Energy Agency left Tehran Monday after arriving Sunday, but there was no word of progress on a thorny issue.

Massimo Aparo, IAEA deputy director general, led a delegation billed by Iran as addressing “outstanding issues,” widely taken to refer to an impasse over uranium traces found by the agency in Iran in sites not declared as nuclear-related. The IAEA said Sunday it planned no public statement, and the Iranian news agency ISNA merely reported meetings – which included Mohammad Eslami, head of the Atomic Energy Organization of Iran – had addressed “future joint cooperation and programs, in addition to safeguarding issues.”

The IAEA has been seeking clarity over the uranium traces, found last year in sites linked to Iran’s nuclear work before 2003. The agency argues Tehran should provide satisfactory answers as part of its ‘safeguards’ obligations under the Nuclear Non-Proliferation Treaty.

But the IAEA probe has become entangled with efforts to restore the 2015 Iran nuclear agreement, the JCPOA (Joint Comprehensive Plan of Action). Tehran has said the IAEA should drop is enquiry which it says began only after Israel in 2018 made a raft of allegations during efforts to back United States President Donald Trump in withdrawing the US from the JCPOA and imposing draconian sanctions on Iran.

The 35-member IAEA board in June and November passed US-drafted motions condemning Iran over not satisfying the agency. Opposing the move, China and Russia said it would stymie talks to restore the JCPOA.