(AFP) - The head of the UN's nuclear watchdog called Monday on Iran to ensure "timely and proactive cooperation" with inspections mandated under the 2015 deal with world powers over its nuclear program.

Speaking at the first meeting of the IAEA's board of governors since US President Donald Trump threw the future of the deal in doubt in May with his decision to withdraw, Director General Yukiya Amano said the agency had had access to all sites in Iran that it needed to visit.

However, as in the agency's last report on Iran in May, Amano said that "timely and proactive cooperation by Iran in providing such access would facilitate implementation... and enhance confidence".

In its last report the IAEA confirmed that Iran was still implementing the accord.

A senior diplomat in Vienna, where the IAEA is based, said the call for timely cooperation did not mean that Iran had breached any of the rules of the accord but that the agency was "encouraging (Iran) to go above and beyond the requirements" of the deal.

Tehran could, for example, invite inspectors to sites they had not demanded access to, the diplomat said.

The other signatories to the 2015 Joint Comprehensive Plan of Action (JCPOA) have been scrambling to find ways to keep it going since Trump's announcement that he would pull out and reinstate US sanctions.

Last month, a senior Iranian official said Trump's actions had left the landmark accord in "intensive care".

As its price for staying in the deal, Iran has demanded European powers present an "economic package" to Iran that would mitigate the effects of US sanctions.

Tehran has threatened to restart its uranium enrichment program at an "industrial level" if the 2015 pact falls apart.