He has been making phone calls as part of efforts to stop conflict between Iran and Israel.

He expressed his condemnation of any military escalation and his deep concern about intensified attacks, but also his long-held position on the need for diplomatic solution to the Iranian nuclear issue, saying "And he’s been repeating that with all of his interlocutors."

For his part, Director General of the International Atomic Energy Agency (IAEA), Rafael Mariano Grossi, said "military escalation threatens lives, increases the chance of a radiological release with serious consequences for people and the environment and delays indispensable work towards a diplomatic solution for the long-term assurance that Iran does not acquire a nuclear weapon."

"Consistent with the objectives of the IAEA and its Statute, I call on all parties to exercise maximum restraint to avoid further escalation," he added.

He also stressed support for a diplomatic solution to the problems posed by the Iranian nuclear program.

"I urge you to pursue every possible diplomatic avenue and I assure you that I remain ready to play my part, including by travelling at the earliest possibility to assess the situation and ensure safety, security and non-proliferation in Iran," he said.